I don't have a problem with opinions. Everyone has one. But as with everything there's a place for them. This forum is one of them.
That said, I have a huge problem when opinion is taken as truth, taking the place of proven facts. So much of that is going on in real life in general that I have an exceptionally low tolerance for it anymore and find it completely unacceptable. When society intentionally becomes ignorant just because it's fashionable that's a massive problem.
Just as bad, I also have a problem with unwarranted incindiary remarks that are masked as opinion. I know I've made my fair share of them in the past and that's just the NYer in me. Trust me when I say I'm becoming a lot more civil with age.