I think that's an easy bias to fall for, but also not actually true. If it were true, the world would only ever monotonically get more and more violent over time, until we lived in some kind of exaggerated parody of an apocalypse slasher film, which is not the case.
Sustainable naïve niceness does not exist as the norm. It is still possible to be kind as a default without immediately rolling over for anybody who does not share such values, even if you sometimes have to do so by reciprocating hostility where it is encountered.
Cruelty and conflict are ultimately destructive forces, wasting goodwill, physical resources, and cooperative potential. The social equilibrium may not bend towards kindness as sharply as we would like sometimes, but it certainly isn't a straight drop to apathy and cynicism either. Although perceiving and portraying something as inevitable can go a long way to rationalizing it, or to trying to justify giving up.
The issue I take with that is that as the problem is entirely social in nature, the perception of futility is also a self-fulfilling prophecy.
The only difference is Apple has the $$ and incentives to remove it as soon as it's brought to their attention (assuming it's actual malware that may cause large financial loss not just copyright infringement).
Alt-stores will be ridden with malware and nobody is going to be legally responsible for it. We can just hope the alt-stores that end up existing have incentives to keep them "clean".
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.