Did you personally have unfriendly arguments with Haskellers? I personally find them quite helpful and friendly on the freenode #haskell channel.
Although there have been heated public disagreements, I haven't seen the people trying to destroy one another. They just have very strong disagreements. That doesn't bother me directly since I'm not in those discussions. The most I can say is that the lack of unity means there is a shortage of "best practice" of how to do certain things and lower community focus in advancing the ecosystem.
Overall most people are friendly in almost all communities, at least if you avoid community-defining topics. So most interactions with haskellers have been friendly. But I had a number of relevant interactions that were Fairly hostile and I have passively observed interactions on various communication channels that wouldn't have flown in the python community.
Although there have been heated public disagreements, I haven't seen the people trying to destroy one another. They just have very strong disagreements. That doesn't bother me directly since I'm not in those discussions. The most I can say is that the lack of unity means there is a shortage of "best practice" of how to do certain things and lower community focus in advancing the ecosystem.