It's not a joke. Rachel Dolezal is the victim of a lot of hate from a lot of people, and has become the go-to butt of the trans-"joke" on the regressive end of the political spectrum.
Of course you will always have the stereotypical transphobes who hate all things trans to begin with – they immediately took the opportunity to pounce on this new version of trans that they weren’t previously aware of – but you also have ignorant people who claim to support trans rights and yet spit in the face of Rachel.
Yes. A lot of the anti-transracial hate is in fact coming from our own progressive camp, and we're well overdue in dealing with it.
For some reason we have fallen into the trap of assuming that there is only “one” type of trans person out there. This is actually not true and if you consider one valid, you should definitely do the same for the other. To say that trans folks no longer exists when we intersect with race is an example of biological essentialism, a racist alt-right idea.
Transracial folks have long since been accepted as real and valid by academia. The 2016 book Trans: Gender and Race in an Age of Unsettled Identities by UCLA sociology professor Rogers Brubaker reveals that transracialism is psychologically real to many people, and there are many examples of transracial folks throughout history.
There is literally no reason to not accept and validate a transracial person if we are accepting of a transgender person. Although for some reason controversial, biological sex is not something that can ever be changed and yet transgender people perceive themselves as the opposite SEX and have SEX REASSIGNMENT SURGERY. Therefore they are attempting to alter something that cannot biologically be altered, but this is okay because they cannot help the way they perceive themselves and the only way to feel as though their body matches who they are inside is to change it to appear the way they feel it should appear.
This is the exact same thing that transracial people are doing. They feel as though they were born the wrong race (something that you cannot change biologically) and they decide to transition so that their outward appearance matches how they are inside. A transwoman is a woman and a transracial woman is her preferred race. We as feminists need to stop demonizing people who are transracial because it makes us hypocrites.
It is not acceptable to tell someone who is transracial that they don’t know what it is like to grow up as that race, when a trans woman does not know what it’s like to grow up as a female either because more than likely they were raised to be male before their parents understood how wrong and unfair that was.
It's called inclusivity for a reason
We need to embrace transracial people the same way we embrace transgender people, it makes no sense any other way. You cannot invalidate a transracial person and then scream and cry when a transgender person is invalidated. You need to open your eyes and embrace both.
Chances are you will never know what it is like to be born as the wrong sex or the wrong race, so you have no right to tell these people that their perception of themselves is wrong.
Sadly even in our own progressive community there is still a lot of growing that needs to occur. So, reach out to your transracial peer, apologize for your ignorance, and tell them you accept and love them. Tell them they are valid, as are you.