There's a tendency among people who are Political Online and have radical politics to point to human nature as a way to win arguments. Every group does this, from neo-fascists who make overly specific claims about how racial lines are boundaries that are impossible to cross, anarchists who point out that there's a history of cooperation and mutual support between individuals and even libertarians who think that because children are awful at sharing private property is natural.
Here's the thing. I think there exists anthropological evidence to make pretty strong arguments for all of these cases (well maybe not the libertarian one). The most obvious problem with making appeals to human nature is that a) humans are complex as fuck and are capable of adapting to a multitude of social environments, b) the historical record and the diversity of societies we've seen means you can pretty much argue any position you want if you narrow down the parameters enough (obviously serious anthropologists are exempt from this). Certainly there exist social arrangements that are superior, but even then it comes down to a question of taste, the alienated fascist who seeks an unchanging ethnostate with so-called traditional gender roles enforced might actually function better in it then a liberated anarchist region with considerably more individual autonomy then what we see today.
However my main problem with appeals to human nature however is they create a myopia which obscures more serious issues. Did the USSR fail because it was working against human nature, or did it fail because of an inability to properly process information and coordinate? By invoking human nature we can stop short of our inquiries. Nothing more to see here folks, no unpacking the absolutely monuments implications that the subjectivity argument has for literally every aspect of human nature. Hayek's analysis is a stick to hit Reds with and nothing more.
Likewise with Marxists (and some anarchists, unfortunately) who have detailed critiques of the alienation that capitalism and the human suffering that results ignore other ways in which individual agency can be suppressed. Detailed critiques of individuals being squashed under machinery of which they have no control over, only to be remedied through... what? endless meetings, attempts to bureaucratize and rationalize information, all done in an attempts to imitate the market without there ever actually being a market.
In all of these examples there is a timidity, a lack of a drive to dig further and fully explore the implications of the arguments these individuals make. The recently converted anarchist imploring people to read Kropoktin fails to look into evolutionary theory more broadly, despite serious developments since the printing of Mutual Aid: A Factor of Evolution. For example do anarcho-communists have an analysis of Hamilton's Rule, a more rigorous analysis of Kropotkin's argument that shows that mutual aid is indeed valuable, but only for members of that individual's 'kin group'. How does this affect the argument in Mutual Aid? Does it make the argument involved more appealing for fascists seeking close-knit groups (especially those who hate capitalism just as much as socialism), rather then cosmopolitan anarchists? If so should we retain the argument? How should be build on it to make it more difficult for reactionaries to corrupt? These are important questions that should be seriously considered.
Such complications are not insurmountable. But they show the problem with relying on surface level analysis of phenomena. Appeals to human nature make individuals lazy and outdated analysis leaves one with a poor framework to argue from. The most obvious example today are reactionaries that argue against attempts to liberate sex and gender with analysis of surface level statistics and the assumption that Western society is the Way It's Always Been. They sustain themselves largely through institutional and social momentum but in the long term the only real way they can get what they want is through coercive mechanisms. It's certainly not a guaranteed victory against them but it will be a downhill battle simply as a result of having a much clearer lay of the land ahead of us.
Human nature is effectively a stop sign for inquiry. If human nature is "bad" then any attempts at freedom are dead in the cradle and we should save ourselves the trouble now. However more troubling is if human nature is "good" - we can just ignore the areas covered and not bother with analysis. No need for further exploration if we know it'll just work out in the end. Not to mention the normative problems that lurk just beneath concerning how to feel about queer, neurodivergent or disabled individuals. The violence of assuming certain ways of being are the default (and therefore) good is well understood among the left and while I'm sure there are those who appeal to human nature with the best intentions it still leaves a crack open for reaction to sneak in. Handwavy appeals to history, evolution and anthropology do violence to the complex creatures that we are. Human nature is a pointless ideological battleground in which the myopia of assumptions indiviudals come with inbuilt make conclusions and victories almost impossible. This is not to say we should consider human nature taboo - heuristics about your local area are of course useful and it can serve as a quick summation of meta-theories about culture/psychology/ethics/biology/etc. But the epemistic damage that this does is significant and should not be ignored. Lazy heuristics are useful for short term problem solving but when it comes to serious pathfinding going forward they carry structural problems that they cannot easily resolve.