Thoughts on feminine boys in BLs?

I see alot of ppl hate on twinks in BLs which i understand cause they tend to look like 16yos or UwU save me *cries* but other than that what is the other reason? Twinks exist irl and I, as a bisexual man likes them too cause I ain't gonna lie they're everywhere but anyways may I ask why? since some ppl act like those feminine men don't exist irl and are very pretty common and that they make it seem like "we should only like masc men." Why erm some think that? /gen