It seems to me that the problem you rightly pointed out could be approached and possibly solved by zooming in a bit and breaking the term "decentralized" into component parts. For example, at least two parts: 1) Those components of decentralization which do not lead to this problem and 2) those components which may lead to this problem.
This simple typology could then, with a bit of nudging, probably yield some new leverage points.
A question like, "what is the _most decentralized_ platform which does _not seem to have this problem_ and what are its characteristics" could also probably help.
We are just getting started with decentralization in many ways, so there may also be analogs in e.g. economics or even games/sports that could be overlaid to improve our optics.
(It'd be neat if we could be really persistent with our decentralization aims as a community and make visible, helpful progress against previous conceptions of the pitfalls)
Unfortunately decentralized tech always ends up harboring illegal or immoral content and then becomes a pariah if a sort.