I won't argue I'm "bitter" (whatever that means) but I'm certainly not angry.
You should take a look at my perspective. I indulge others in conversations and participate in debates with them, hoping for some intellectual discourse. I want to be proven wrong or to educate someone. The resulting conversation is only to find out they literally do not even comprehend what is being discussed, do not even attempt to communicate by trying to understand other's points, and often seem to be making all kinds of irrational assumptions that have absolutely no bearing on the conversation.
The entire conversation was a sham from the start. They never had any intention of listening to anything anyone else had to say, and just wanted to argue for the sake of arguing.
So in other words: I gladly participate with them up to the point in which I realize they are some arrogant moron or childish troll wanting nothing more than to stroke their own ego and ejaculate cognitive bias all over my face. So I then write them off as an idiot, tell them this directly, and recently place them on ignore right afterwards.
There is little else you can do. You cannot reason with trolls, you cannot have rational conversations with people controlled by extreme cognitive biases and close minded predispositions. So I try to have fun with them after I realize they just trolled me and wasted my time and thoughts. It's the least I could get from them after their lunacy.
I give everyone an equal shake. If you're reasonable, I will agree to disagree, concede as much as I believe should be conceded, or simply end the conversation. If you're unreasonable, like most people here- I will not realize this until it's too late and then insult you because that is me being as honest as possible.
TLDR: I don't insult people who don't deserve it. Most people here are ignorant morons or unreasonable trolls, so it's not out of this world to find out you were trolled the entire time and then try to get some fun out of it or display your honest thoughts to relieve the disappointment and irrefutable reality that people in this world are seemingly incompetent the majority of the time.