If one company takes a more principled approach to moderation, and that more principled approach is harmful to revenue, that company will be outcompeted by companies with whatever moderation policies optimize for engagement / revenue / growth. As a result, in the absence of legislation, you get adverse selection i.e. the dominant platforms will be the ones that optimize for engagement/revenue/growth, rather than the ones with good moderation policies.
If you instead have legislation for what "good moderation" looks like, it applies equally to all companies and mitigates the adverse selection problem.
Of course, it is still entirely possible for bad legislation to introduce worse problems than the adverse selection problem. It depends on the object level of what exactly the legislation is, rather than being a blanket "legislation bad" or "legislation good" sort of thing.
They do have a rationale. The issue is that it's biased.
Twitter can and do ask for user feedback all the time, without making a press release about it.
I don't find it cynical to ask why they are doing this in public - it seems likely that the parent has hit upon a good part of the reason.
I would like to point out that regarding moderation, tech companies have been asking for guidelines and new laws for a decade now. Ageing lawmakers have been unable to provide them and we start to see shy initiatives from the EU regarding privacy laws but roughly most of the water in which tech companies operate are still no mans lands.
All that make me think that even tough you're right that the end result will not be democratic, I wouldn't throw them the stone and accuse them of acting in bad faith.