If a man identifies as a woman, that initially seems like it defies reality, because they are a male, not a female. But advocates of transgenderism have said that gender and sex are not the same thing. Gender is neurological, and sex is biological. And because of that, people have said that the state of your gender is independent of your sex. If it's a different thing, then it's not defying reality to say your gender is different from your sex.
But if you ask most of these people if people should be able to change their skin color, most of them would say no. Some might even go as far as to say that that's racist. But why? After all, you can separate neurological and biological race the same way you can separate gender and sex. If we apply the exact same rules, then a white person who identifies as black is not "denying reality," because their neurological race is independent of their biological race.
And since transgender people are allowed to permanently change their bodies with surgery in order to align their physical form with their gender as much as possible, at least when they're 18, then "transrace" individuals should be able to do the same: tattoo their body all over with the skin color they want.
But in terms of neurological race, how exactly can you "feel" black? Well, the same way you can "feel" female: cultural norms that firmly establish specific ideas with specific genders. Thus, gender becomes apart of our identity. Without this, you become like trees, which do have male and female, but you cannot possibly tell the difference and you don't feel the difference. And yet, race also has cultural norms that firmly establish specific ideas to specific races. It's called culture. There's black culture, white culture, Mexican culture, Japanese culture, etc. So a person can in fact "feel black" even if they are white.
As you can see, the exact same rules can absolutely apply to race, which is troubling for some advocates of transgenderism, because they don't want that, but they do still want transgenderism. The only differences that gender has with race are irrelevant things that do not break the foundation of pro-transracism, such as the strength differences between sexes vs the lack of strength differences between races.
Conclusion: Transgenderism and transracism are approved by the same logic. Therefore, if transgenderism is allowed, transracism should be too.
One can support transgenderism without supporting transracism.
Because they are not same things, no logical contradiction happens if person supports one and not the other.
If person said "I support A", and also said "I don't support A", that would be a logical contradiction.
However, no such thing happens here.
Your argument tries to expose logical contradiction in reasons.
For example, supporting A and not supporting B, is not logically contradictive.
But if reasons for supporting A are same reasons which support B, then logical justification for not supporting B ceases.
However, moral reasons, being arbitrary, always allow exclusions.
For example, person can say "I support transgenderism for these reasons", and those reasons exclude transracism.
So, for example, one can say "Person can identify with what person wants to be, and that becomes person's identity, except when it comes to race".
This produces no contradiction, and is a logical standard which supports transgenderism and doesn't support transracism.
One can raise a critique that this standard is arbitrary, but all standards of reasons to support something are - arbitrary.
So any critique raised against this standard would be raised against any standard.
One could support transgenderism but oppose transracialism based on a cost-benefit analysis. Let's suppose that in each case, allowing people to identify as they wish will make those people happier but cause some amount of social friction and offense. The difference is that society has already normalized transgender identity to a large enough extent that a lot of people are going to view themselves as transgender no matter what even if society tells them they're incorrect, and most of the offense from changing gender norms has already happened such that people have just accepted/gotten desensitized to it.
Since a lot of people view themselves as transgender already, the genie is out of the bottle. The happiness and mental health of a lot of people depends on how well transgender identity is accepted. While people wearing clothing associated with other sexes may have been controversial at first, it's now ubiquitous enough that more people continuing to do so isn't going to cause much additional offense.
In contrast, very few people identify as transracial, so the aggregate benefit to mental health from supporting transracialism is much lower. And things like blackface or white people saying the n-word are still stigmatized enough that they would cause significant offense if even just a few high profile people did them. So the costs for promoting transracial identities are much higher, and the benefits much lower.
