This is absolutely the reason. Except in the case of black people, for which it was something imposed by white people during the Clinton administration as a sor

This is absolutely the reason. Except in the case of black people, for which it was something imposed by white people during the Clinton administration as a sort of twisted apology for destroying the Rainbow Coalition (who popularized "African-American.") Once people saw that slaves and their descendants might be compensated in some way, or treated in a special way by government in lieu of compensation, they all wanted to become black. So after 1965 (the end of legal segregation in the US) they started hyphenating their ethnicities, or in the case of "hispanic," making up new ethnicities from whole cloth. Compensation for slavery isn't "free stuff." You should give up your inheritance.