Is it normal that gays don't find trannies sexually attractive ?

If the other person does not find the other attractive then that's OK.

I have heard that a lot of trannies end up with other trannies. It's not uncommon for gay, and straight people to not be attracted to transgendered people. People who are not attracted to trans people are not transphobic. Everyone just likes who they like, and if someone likes another person who doesn't reciprocate those feelings it really doesn't mean much of anything, and isn't a tragedy to anyone other than the person who has been rejected. Too bad, so sad.

If I like some dude who only likes tall women with naturally blonde hair, and green eyes, he's not phobic of redheads, and brunettes with blue, or brown eyes. I would just need to accept reality, and move on with my life. It's not a tragedy to anyone except me when I feel the rejection. No one owes it to me to return my interest in them if they don't want to do so.

No, because when a gay guys says the are attracted to a man they mean they are attracted to a BIOLOGICAL males. The same how homosexual women are attracted to BIOLOGICAL females.

Trans people are not the biological sex they are portraying. The sexual preferences rely on the biological components of the two individuals. Heterosexuals Male+Female. Homosexuals Male+Male = Female+Female.

Portraying yourself as a different sex doesnt suddenly change your biological innate sex. Thus people who dislike someone portraying the sex that they perfer is not discriminatory since they are objectively NOT the sex the person is into.

The word you are looking for are pansexuals. Pansexuals make their decisions based on the personality of the individual rather than their physical sex. Which is more apt for the given situation rather than the more straightforward descriptors such as heterosexual and homosexual.

"Trannie" is short for transvestite, not transgender person.
A transgender woman is a woman who was unfortunate enough to be born with a male body. A transvestite is a man who sometimes likes to dress up as a woman, but doesn't actually want to be one.

If a straight woman desires a trans man, they're both considered straight. a trans man is still a man, even if they have some female parts.

I wouldn't say it's normal to call lesbians who aren't into trans woman transphobic. Like RosaIsabella said: everyone just likes who they like. It sucks to get rejected, but to call someone transphobic over that is not normal.