Because you are correct, making top level posts on a twitter-like social media constantly with this ethos was actually so emotionally exhausting for me it physically affected my health, but the solution to that is just to not do that anymore.
Also, I do this not because I've arbitrarily decided that I've got to bear this cross, as you say, but because it is my default mode of interaction, in fact the only one I know, and it's something I very much like about myself that I always interact in this manner, and I think trying to learn how to be less genuine and less invested and less open, even if just for my online interactions, would sincerely leak out into my character in general in a way I don't like. So I'm not really doing it out of a sense of duty, but essentially out of a sense of convenience, because I don't want to have to go through the effort of learning how to context switch between a mode of interaction for being online and a mode of interaction for being offline.
Just as easily as, seeing the harsh and uncaring nature of the world, we could imitate and perpetuate it deterministically, we also could see that harsh and uncaring nature, and choose to be more caring, compassionate, and understanding as an equally inevitable reaction, a rejection or countermeasure to it. It isn't free will, it's just that our individual experiences and personalities as people determine how we process and predicate our actions on what the world is like, and so we can all choose differently.
And in fact, even the exhortations and rationale of strangers are part of the stimuli in the world that may change how you act. Which is why I think it is worth it to say what I'm saying now.
Superficial determinism is the hobgoblin of little minds.
Personally, while I am not always nice on the internet because I struggled to countenance fools, rationalizations, and people who lie to themselves, which happens surprisingly often, I do really try, and more importantly even if I am not nice, even at my least nice, I try to always be as genuine and authentic as possible, and always be open to having my mind changed and genuinely put my beliefs on the line. And I think that in itself can be surprising and refreshing for the people I interact with.