Yoshi-P has always had a don't ask, don't tell policy regarding cheating.

Mostly it's practicality. A lot of Anti cheat are essentially Root-kits and they are illegal in some jurisdictions. Also, they have to be constantly maintained and updated, which is expensive whether developing your own or contracting out third party. A good chunk of the community also uses mods. Most of them are cosmetic, but there are also QoL mods which in some cases fix issues the game has had since launch (removing clipping), add features which should've been in since launch and will soon be added (chat bubbles), or even help with accessibility issues some players may have (condensing skill chains).

Considering the game is mostly PVE, and the competitive PVE aspect only impacts a tiny portion of the already tiny portion of the playerbase that does the content, it's probably easier to focus on them to verify for cheating and punishing players who openly engage to the point they're getting reported.