Can somebody explain to me what the argument for being pro-life is?

It's a typically religious argument, but even if you drop the religious component, there is still the issue of roughly where you draw the line. It also depends on what your criteria for value are. If the criterion in question is a being's humanity, then it's conceivable to hold to hard line anti-abortion positions. If you think something's humanity is not a strong enough criterion, you might use the more philosophically sophisticated notion of "personhood."

Historically, Christianity has had problems with abortion. The question of when "ensoulment" occurs has plagued their theologians for some time. In Medieval times, some of their thinkers believed it occurred when the fetus first moved independently, and before that the fetus was just a lump of tissue. More recently, lots of Christians have come to the conclusion that it basically happens at the moment that the gametes fuse (the claim that "life begins at conception"). However, Christians don't talk about "ensoulment" as such these days, because we live in a secular society, and you can't sell openly sectarian notions here quite so easily. So they use the more neutral term "life" (even though, of course, the gametes were alive prior to the creation of the zygote, and the zygote is alive before it becomes an embryo, and so on).

The rough idea is that no individual gamete on its own can become a natural-born human being, but a zygote can. Therefore the zygote should be accorded all the basic rights and protections accorded to any other person in our society. Of course, this ignores the fact that many fertilized eggs are deposited improperly, causing things like ectopic pregnancies. It also seems to potentially commit the genetic fallacy (a zygote or an embryo is no more a person, it can be said, than a seed is a tree).

Regardless, the religious people advancing this argument are just favoring one extreme of the spectrum. But assume you want to be more rational about it, or at least have more nuanced judgment. Suppose you admit that, yes, an embryo is not a person any more than a seed is a tree, but whereas it may take a long time for a seed to become a tree, it doesn't take very long at all for an embryo to become a person. And suppose, as most people do, that you rule infanticide out from the get-go. The rapidity of the development means that it becomes somewhat important where you draw the line. How close to the line of birth are you willing to go before you say abortion is basically morally equivalent to infanticide? If you just adopt birth as the line of demarcation, then you're openly admitting to the arbitrariness of the line you choose to draw.

But there are problems with any line you might want to draw. Trimesters are equally arbitrary in their own ways, and we simply don't have the tools to determine when the fetus has a sufficiently developed neural system to, say, feel pain, or have cognition of any recognizable sort, or even necessarily to survive independently outside the womb. So we're left throwing darts in the dark. When does the mass of tissue we call a fetus have the qualities we recognize in other persons? When can it survive outside the womb?

You see the problems that this runs into. Pro-choice hard liners, by contrast, will of course object that this is in some sense irrelevant, because it's the woman's body. They'll bring up thought experiments such as the dialysis patient whose survival is dependent on being hooked up to one of your kidneys and things like that. But this too is a form of extremism, since it arbitrarily privileges one person's life, or specifically one kind of person's mode of life, above that of another.

In any event, I'm basically comfortable with drawing the line at the arbitrary third trimester, since I'm sufficiently uncomfortable with the arbitrariness of drawing the line at birth, but then again in extreme cases I would consider infanticide justifiable (although not desirable). There are arguments which I find compelling that make it largely indistinguishable from late-term abortion, and if you're okay with late-term abortions, then...

All that said, yes, I do agree with you, the attacks on Planned Parenthood are rather ignorant and unfortunate. That organization offers much-needed services to women that they often can't get as easily anywhere else.

As opposed to being pro baby killers?

I will never say I am "pro-life," but from my stance it's about owning up to your actions. My problem is with the reasoning of the parents not whether it's alive or not.

There's a few different arguments but the biggest reason for people being pro-life is religious morality that committing an abortion is somehow against god or something. It usually has to do with this idea that pregnancy and sex are holy. It's why a lot of Christians think that condoms and birth control are also sacrilegious.

how hard is it to not get pregnant

There are many arguments. They range from 'responsibility' to 'considering how early the heart of the fetus develops'

Sure, if you believe that the fetus deserves to live.

Personally, I'm not entirely comfortable with abortion. Ideally very child could be born and grow up in a loving household free from poverty and the like...but this isn't a perfect world, and I certainly wouldn't use the law to force women to carry pregnancies they don't want to have. Probably the best thing pro-lifers could do is put their money where their mouth is, and form institutions that make raising children a more viable option for women, and tend to the welfare of the child. But wait, oh, they don't want poor people to have kids either. Don't have kids you can't afford, but don't have abortions, and don't look for birth control to be in your insurance package. Now that I think about it, it is interesting how much control of sex and reproduction is politicized.

My only concern is not rape, not condoms breaking not birth control failing but what if the pregnancy is a risk to the mothers health, what if having a pregnancy could kill the mother otherwise in planned pregnancies could go up for adoption if need be.

Women are allowed to decided if the pregnancy caused complications and threaten her life. She also can decided to keep or not if its a due to rape (I hate this word so much but I had to use it here for education purpose ).

Not for those, who were messing around and being lazy, and got into it. That Child must not be put away once the zygote has formed.

AMEN

And for some reason they assume women that gets abortion as a birth control method. Birth control isn't hard to get so, I have no idea where they got that from and they love saying thins like "You should have kept your legs closed" which IMO is unhealthy because it's insinuating that sex is bad.