Trying to explain discrimination to a guy who has never been the target of discrimination is pretty frustrating sometimes. Specifically when he acts like someone being specifically protected under the law makes him less protected...

Ugh....

Here's the deal.
When a person is targeted because of their sexuality/gender identity/race/sex/disability they are the victim of a hate crime. These crimes are not just a threat to one person, they are a threat to an entire group of people.
When someone kills a black man for being black, they are likely to victimize other black people. When someone kills a man over an argument about a barking dog, and the victim happens to be black, they are a shitty person but they are not as likely to go around killing other people just for having a barking dog. In the first case race is the only or primary factor, in the second case race is of little importance and the argument is the primary motivation for the murder.
It's the same reason we charge involuntary manslaughter differently from premeditated homicide.

Oh but, now we're saying it's more okay to kill someone by accident! Yeah, he used that logic that by having laws against hate crimes we're saying it's more okay to murder someone over a barking dog than because of their race.
This is not a sliding scale of badness. It's taking into account the INTENT of the person charged.

"Where does it end? If we have special protections for transpeople, then why not people with green eyes?"
Uh... because people with green eyes don't have multiple hate groups targeting them. If anyone goes around murdering people with green eyes its more a specific pathology. The entire community of people with green eyes are not likely to be worried that they will be the next target of some random attack, they are not talking about how it's just like that time someone else with green eyes got murdered in another state. However, there are multiple hate groups and just plain hateful individuals that go about attacking people because of their race/gender identity/sex/sexuality/disability/. When a gay man gets stabbed on the street outside of a gay club, then a whole community has to wonder if they could be next.

I don't know why this is hard for some people to understand. Like are you jealous that some folks are getting much needed protection??? Were you the kind of child that pitched a fit that it wasn't fair that the kid in a wheelchair didn't have run laps in gym?