It is insincere pandering to claim to relate to legitimate struggles of an ethnic group by acting like you are part of that group, when in reality you grew up completely separate from that group and aren’t even the same ethnicity.

I think the confusing part is when people act like they are offended by this when really they wouldn’t care if not for being opposed to the person politically. So it’s like insincere mimicry of offense at insincere mimicry.