She was also young and desperate enough to just cling to the one person offering her a life other than slavery. And we learn in Elogium she only really has sexual urges once in her lifetime. One could possibly surmise even that Ocampans are only heterosexual during Elogium and aesexual for the rest of their lives, and that Kes uses her sexuality as a way to bond with aliens she feels spiritually close to and who do not have such biological characteristics.
But you are correct that the show itself gives us no reason to come to such conclusions.
There is a difference between finding something harmless morally wrong and using that belief as a justification to bully or verbally attack people you don't agree with on the internet.