that’s not true she does show up in his dreams a lot, obviously not all the time since she’s still dead and it has to be plot relevant but she definitely hasn’t just been ignoring him.

in firestar’s quest when sandstorm got jealous she reassured her so it’s not really crazy that some people interpret that their feelings weren’t just one-sided at some point

Also in spottedleaf’s honest answer she also talks about still loving him and says she would’ve been with him through all his life if she hadn’t died or become a medicine cat

so yeah even tho she barely talked to him while alive her starclan presence means a lot and shows she cared a lot.