Why muslim terrorists kill other muslim terrorists?

Same reasons that the Protestants and the Catholics fought so bitterly in Europe for so long. They think the others are worshipping the right god the wrong way and they need to convert or die.

Because they are Muslim Terrorists and they think Allah approves.

How are you on the past (and current) murders that happened in Northern Ireland and on the mainland due to Protestants and Catholics wanting things 'their 'way?

Throw in that there were various fund raising events that were arranged in the USA to fund the PIRA. I had an ex who was caught up in the PIRA bombing in Manchester that covered her and her daughter in glass from the explosion.

The current military of Iran are terrorists because?

Iran has been fighting ISIS since the beginning. A good deal of ISIS's support comes from Saudi Arabia a US "Ally", who Iran is locked in a regional "cold" conflict with.

You can call it Muslims vs Muslim, if you want, but it would be like calling WWI a Christian vs Christian war.

Khuzistan, is an Iranian province. Part of the population, considers itself Arab. About 20 years ago, the Arab regimes, that historically opposed Iran, encouraged extremists, form some sort of Ahwaz liberation front (or some similar name). Ahwaz is how the Separatists use to refer to Khuzistan.

So, over the past 20 years or so, the separatist organization, has been conducted terror attacks in Khuzistan. Saudi Arabia, has been arming, and financing the Ahmaz separatists, their latest attack, consisted of four militants, emerging from the stands, and firing automatic weapons into a crows, during a military parade, and killing 8-9 soldiers, and around 20 civilians (children included).

We support Saudi Arabia, because Trump and his son-in-law, are brokering a deal, to make the Trump extended family, a lot of money (to make a long story short).

I get ISIS being a terrorist, but the military of Iran? How are they like ISIS?

Iranian military are terrorists? Since when?

Its in their holy book to kill non believers. If the other guy does not believe (the way you believe) you are justified in killing him. Even mohammed killed all them members of a mosque. As we Christians say "The devil hates - even his own"

What do you mean with "now"? Sunni extremists like Al Qaeda and the Islamic State have been killing Shiites like the Iranians for a long time.

Terrorists (backed by the US and other western countries) attacking the army of a sovereign country.

There are stories of the on sect feasting on tables made by piling up the bodies of the other sect. They are pretty determined in their beliefs.

simple, they're stupid and single minded/purposed, they'll blow their own families up in the name of "allah"...

You’re pretty quick, son.

I didn't know the Iranian military are terrorists