It very neatly describes the way liberals see the world and political struggle.
Lots of people complain about the anti-climatic ending, but really I don't think it could any other way. I'd like to imagine that there's some alternate universe where Kōhei Horikoshi actually believed in something and Deku was actually built up as the anti-All4One he was only hinted as being in the beginning of the story. Where he opposes all the many injustices of the hero world and determines to change their frequently backwards, insular, contradictory society for the better, and forms his own faction antithetical to the League of Villains and when he finally has his showdown with All4One, Harry surpasses by adopting new methods, breaking the rules and embracing change and the progression of history. While All4One clings to an idyllic imagining of the past and the greatest extent of his dreams is to become the self-appointed god of a eternally stagnant Neverland. Deku has embraced the possibility of a shining future and so can overcome the self-imposed limits All4One could never cross, and All4One is ultimately defeated by this.
But that would require a Deku that believed in something. and since Kōhei Horikoshi is a liberal centrist Blairite that doesn't really believe in anything, Deku can't believe in anything. Deku lives in a world drought with conflict and injustice, a stratified class society, horrendous oppression of the heroes with ugly quirks, the absurd charade the hero world puts up to enforce their own self-segregation, a corrupted and bureaucracy-chocked government, rampant racism, so on and so forth. But Deku is little more than a passive observer for most of it, only the racism really bothers him (and then only racism towards quirk people). In fact, when the Meta Liberation Front stands up against the institutionalisation of dangerous quirk holders and even segregation based on quirk, they're depicted as some kind of evil for doing so. For opposing segregation. In the end, the biggest advocate for change is All4One and Deku and friends only ever fight for the preservation and reproduction of the status quo. The very height of Deku's dreams is to join the heroes, a sort of FBI and the ultimate defenders of the hero world status quo. One4All and the League of Villains are the big instigators of change and Deku never quite gets to One4All's level. Deku doesn't even beat One4All, One4All accidentally kills himself because he violated some obscure technicality where his own arrogance causes him to rewind himself out of existence.
And this is really the struggle of liberals, they live in a world fraught with conflict, but aren't particularly bothered by any of it except those that threaten the multicultural pluralism. They see change, and the force behind that change, as a wholly negative phenomenon. Even then, they can only act within the legal and ideological framework of their society. So for instance, instead of organizing Insurrectionary and disruptive activity against Trump and the far-right, all they can do is bang their drum about what a racist bigot he is and hope they can catch him violating some technicality that will allow them to have him impeached or at least destroy his political clout. It won't work, it will never work, but that is the limit of liberalism just as it was the limit of My Hero Academia.
I repeat what I said before, that "heroes defend the status quo" is not remotely unique to MHA and the "Liberation Front" plot point is shitty, but ultimately MHA is ideologically not half as rancid as "ethical slavery" HP. It's genuinely above-average for the social messaging of a superhero story.
Also, MHA simultaneously has a much clearer sense of empathy for people who went down the wrong path and it also has an understanding that there's nothing wrong with stopping Hitler by killing him (instead of relying on some bullshit plot devise to kill him for you to "keep your hands clean"), two things HP catastrophically lacks. It's technically true that All for One kills himself, but there is no ethical compunction with killing him and it's deliberately facilitated by the protagonists, who were in the process of beating him to death anyway.
I don't like MHA, but this thesis is silly.
Edit: also, he obviously doesn't go far enough, but the whole point of the broader narrative is Deku's Great Man fixation reflecting society's Great Man fixation and he is part of the generation that explicitly replaces "The Symbol" (the lone individual who holds society together) with solidarity and collective action that destroys All for One, something "The Symbol" failed to do.