You can't search/filter for
anything other than type-of-app/game. In fact, they
added the tags for ads/IAPs and hoicked them to the top of the page, rather than sticking them with the rest of the app metadata below the fold. I'd be more willing to think a lack of ad-status filters was nefarious if it was suspiciously missing from a list of other searchable filters.
The fact that they don't have any support for filtering just says to me that they don't really care about app discovery outside of what they build suggested lists for, which seems orthogonal here since some of the suggested lists they curate are literally titled "Ad-free games" (plus "Offline games", "Premium games", "No-interruption games", etc which are also all largely filled with no-ad games, with a few exceptions).
Maybe they're omitting entire features / filter systems just so they don't have to add the sub-ability to just see which apps don't have ads, but I doubt it. As other comments have stated, a lot of people just don't want Amazon-like product titles crammed with keywords on keywords, especially when they're not even checked for correctness. I'm one of those people.
I'd say this probably boils down to a differing fundamental assumption we have: your comment seems to imply you might think big companies are inherently out to maximize profits through manipulating people, even if that means intentionally making a product worse for customers. If that's the case, there's really no point in debating here since that's a completely different conversation and I doubt either of us have the necessary internal evidence needed to convince the other of the real intentions behind withholding this specific feature.