It matches my experiences. I have literally had former libs come back months later and apologise for previous interactions they had with me.

Our interactions do not happen in a vacuum. Zoom out and view things hollistically. I am not the only communist that is going to speak to [belligerent liberal], they are going to encounter others after me. It is NOT possible to turn a liberal in every encounter, moods, daily lives, what kind of shit a person is going through, all kinds of things are out of my control when interacting with a person. The way they interact with me is entirely based on luck.

If luck has it that this person is open minded and has intellectual curiosity then no insults are necessary at all. They are the perfect candidate for education and can be engaged with in good faith. But, as so happens to often be the case, many times the person I interact with is not in this mindset and there is zero chance of turning that person in this single interaction.

My job, holistically, in that situation, is to set this individual up so that the next communist they encounter has an easier time than I have. In order to do that I need to ensure that the behaviours that aren't useful are suitably deterred from occurring again.

I know this works because I have experienced it working dozens of times.

There are times when none of this is necessary, and there are other times when it is beneficial. Being able to judge what to do is a skill that is well worth honing.

The most important skill to learn however is the ability to view yourself and your interactions not as individual interactions but as just one input that exists as part of a whole, a movement. When you understand your interactions on this level then you can tailor your interactions not to the individual level but instead to what benefits the movement as a whole.