By definition, literally any rejection of an intimate advance would make that advance "unwanted". Should we as a society interpret this to mean that the only people allowed to flirt with other people are ones who are successful 100% of the time?
Now, obviously if he persisted after rejection then that changes things, but it doesn't seem like that's been alleged AFAICT.
This is a complete strawman. Sexual harassment is well defined. It would be unwanted and, especially, persistent sexual attention.