So what?
As in election,
Either you vote or you get to STFU and wait for results.
ROFL that's the one of most ridiculous things I've ever read.
No-one would respect an election that only 0.4 of the population voted on. Nor should they.
There is no self-selection bias present which would impact approval rating involved.
Absolute gibberish. The self-selection bias is likely huge, given the nature of the survey and that it even drives away people here.
Also self-selection is accounted for? Unsourced, unsupported rubbish. I work with people who do surveys for a living as well, and self-selection bias is absolutely an issue in our industry (law), so your unsourced, unsupported claim that it's a "solved problem" (a rather extreme claim) seems completely nonsensical.
And gamers? We know the self-selection with gamers means haters are much more likely to finish surveys than people who love something. But the exact percentage varies, so you can't just say "Solved!". Especially not when you're touting a 70% threshold for approval, rather than saying you use a complicated weighted formula. Or are we to presume they're lying re: the 70%?
The extreme bulk majority are ordinary DNDBeyond users.
Unless you have secret insider information, you have absolutely no basis to make that claim. It's just straightforwardly a lie presented as a fact. We cannot be certain who is answering these surveys, only that it's very few people (even compared to the users of D&D Beyond, which was 13 million last time WotC released figures, shortly after they bought it), and that surveys are extremely onerous and completely lack direction and focus.
I mean, unless all you mean by "ordinary DNDBeyond users" is "not people who post on ENworld, in which case it's a pointless and obvious truism. But it seems like you mean more than that.
At this point it looks very like you're just making up a bunch of "facts" that are convenient for you. You no provide no links, no sources, just claims.