Is this real discrimination?

*Sorry if my english is bad :(I recently saw a post on Tumblr, where some people were arguing about that if a person does not feel attracted to transgender people corresponding to their sexual preference, that person was automatically transphobic or if someone does not feel attracted to people of a particular race, that person is automatically racist. First of all, I do not have a specific preference to a race, and about transgender people I'm not completely sure.I found this interesting, so I would like to know your opinions about it!