@samhenrigold they're valid, they're trying to build a fully FOSS ecosystem, they still allow these apps, they are just marked as these. There's also third party repos like IzzyOnDroid, but F-Droid itself has a mission to push for FOSS, and that's kind of it. I see why.
Most people don't even look too closely into these anti feature tags, but some people do like to know this kind of thing, hence these flags are nice to have.
lucasmz, in search results, apps with anti-features lack the install button in the list, requiring an extra click. This feels intentional.