Undrave
Legend
The DnDBeyond stats can't even make the difference between characters built 'just because' and characters being actively played.I just reread the OP and that is not the claim, as far as I can tell.
It alleges that experienced players who enjoying leveraging the rules (a certain playstyle that rhymes with shower tamer) will overwhelmingly choose casters over martials. It does not make this claim of inexperienced players, or of players who do not participate in that approach to the game.
Presumably the survey you showed us was not exclusively directed at experienced players who enjoy leveraging the rules.
And it traditionally skew towards the classes available as free material on the website.