On compassion, I, of course, agree.
On religion... Firstly, I must say up front that, today, when one wants to criticise (or even praise) religion, he doesn't know what's he criticising anymore. From one hand, you have people literally believing in Adam, Eve, and the bearded sadist (read, God). And from the other hand, you have people believing in nothing aforesaid (but God, of course, whatever may it be), people getting virtually none of their ethics from religion. In my school, I have each of the said types. The latter is free on sexuality, free on drugs (ie., believes nothing is wrong with either), free on every thing you can imagine; a guy who interpretates Bible as a work of art.
In the latter case, religion is more a matter of identity, than it is of actual belief. Family tradition, country tradition, etc, all influence him into taking the name 'christian', and yet he finds the actual christian creeeds (such as the sins) to be laughable at. Here, I'll comment only on actual belief in religious philosophical systems.
It's a delusion. Virtually all beliefs of major religions have been disproved. How it affects us? Negatively. Yes, sure, you may have more compassion here and there, more interpersonal connection. But even that has it's cost.
I assume you aren't a speaker of Serbo-Croatian? If you were, I'd recommend you the book by Dušan Nedeljković, 'Nemoralnost besmrtnosti i etička funkcija smrti.' ('Immorality of immortality and the ethical function of death') In it, the author talks on how religion was used by bourgeoisie to tame the people out of revolution and rebellion. You may find similar ideas in some Marxist authors, but of that ideology I lack knowledge.
Apart from this, there were many, many damages of religion identified by various thinkers. Consider the cycle presented by Erich Fromm in his work 'Psychoanalysis and Religion': the religious person suffers; thereby, he comes to God. God is great; thereby, the believer is unworthy. This causes him to suffer even more - and the cycle continues.
Consider, then, its antagonism towards hedonism. Christians believe that the lower, animal pleasures (hedonē) must be repressed, in other to enjoy greater pleasures. (eudaimonia) However, wasn't a research made, which found these two not only to not be two opposites, but to have the correlation of 0.94?! (Perfect correlation would be 1.)
Not even to speak of the quasi-gratification of thinking you understand the world, when you actually don't. Not even to speak of this true understanding, true power of knowledge, being taken away from you. Not to even speak of, wasting the knowledge you do have, on serving an imaginitive entity.
