Welcome to the forum @scarlong!
I think this is because identifiers are a small part of iNat users and assume that whomever they’re identifying for is a casual user and likely won’t engage with the comment? Identifiers also go through hundreds of observations in short amounts of time, so it doesn’t make sense to comment on every nice photo when IDing. Some identifiers commenting habits are discussed in Lack of Reasoning on Disagreements, if you want to understand them more.
However, you can build up a small community of regular observers & identifiers, who ocassionally do comment on your nice photos. This happens with time, the longer you observe and identify, the more likely it’ll happen.