Don't try to defuse situations by telling people to "calm down" it will 100% of the time escalate the situation.

What you're saying makes sense I suppose I've just never seen that happen with someone else.

You've seen it happen. Gamers used to tell everyone they were gonna r**e them, liberals all used to be transphobic (ask any trans person what engaging anywhere on reddit used to be like), lgbt people in general used to receive hate from everyone libs included, etc etc. All these changes did not come from convincing people nicely, they came from forcefully creating a new social paradigm and demanding people to accept it. People can either be uncomfortable, or they can change in order to find comfort. This is what people do.

When it comes to engaging with people regarding ideology such as socialism, this has to be viewed in a hollistic way. There is absolutely 0% chance I can convince the shithead who is gish galloping the usual 30 different propaganda points about the soviet union, stalin, blah blah blah, into engaging with me in good faith. It just can't be done. Whether they're being "civil" or not. Making interactions with these people unenjoyable and uncomfortable for them has the potential to make them change the way they interact with the next socialist they come across. It has the potential to make them act differently because they don't want that uncomfortable experience again. None of our interactions exist in a vacuum, I am not the only socialist you will ever interact with, you will meet hundreds more during the course of our lives, and that future interaction will include decisions you make based on this interaction. A horrible interaction one time gives way to a more positive interaction next time, where that person says "wow I wish someone were as civil about it as you are, last time I got really abusive people" completely ignoring the fact they were being a dick and there was no reason to waste much time/effort on them.

This is the crux of why bullying works. And also why a broad range of tactics is beneficial to the movement.