I think a better, more generic case could be made that concentration of power is dangerous. That power could be physical, as in the case of super soldiers or, more extremely, the Hulk, or it could be technological, as in the case of Stark/Ultron. Heck, widen the perspective a bit and you could also make the case for financial and political power, but I doubt Marvel's going to go all anarchist on us.Sure, the MCU has tried to hamfist this nonsense idea into the franchise, but it really fails most of the time, and the other times are only partial failures.
Age of Ultron isn’t a result of superheroes, it’s a result of a scientist developing AI tech too recklessly. The superheroes then stop the AI monster from murdering humanity or whatever. It’s only to give personal stakes and create internal and interteam struggle that the scientist happens to also be part of the team, but nothing about Ultron’s creation actually relies on the existence of superheroes. In a timeline without supers, Ultron could just as easily come about, and have no one to stop him.
Wandavision and civil war make a spectacle case for oversight of superheroes, for sure, though the incident with Wanda in CW is...extremely normal for US military action abroad, so it falls a bit flat for me.
However, there's one point where Zemo's argument falls very flat, and that is that this is a world with supers anyway. There are aliens with literally god-like powers walking the Earth. There are sorcerers who can rewrite reality and bend time. Random chance endows people with enormous power — Danvers is the most prominent example, but there's also Parker and whatever is going on with Rambeau, plus a whole lot of folks if you include Agents of SHIELD. These are things that happen regardless of the existence of the super-soldier serum. If anything, the serum provides an opportunity to equalize the playing field, by creating supers in a controlled fashion.
A stronger argument would be that the serum in particular is dangerous, because it amplifies negative personality traits more than positive ones — that's why it was so hard for the OSS to find a suitable candidate back in the day.