The argument you presented here is pseudo-profound and very simplistic. It is superficial and ignores why “reverse- racism” is even a thing. But you got some of it right though because none of it as you indicated in your last paragraph is “reverse-racism”. Reverse racism is a myth promulgated by white resentment.
Making fun of white people with thin lips is humorous only if you stereotypically believe that all black people have big lips…which I should not have to tell you is fallacious. My mother has thin lips and there is no European ancestry in her lineage.
Making fun of white people with thin lips may be hilarious if white people have long considered that having full lips is an unattractive, subhuman quality given the longstanding discrimination and prejudice against Blacks who may or may not have full lips. The absurdity reveals itself even more considering the now trendy contradiction of whites with fully injected lips popularly being featured as a mark of beauty.
You can’t have it both ways. That is the punchline of the joke. If you want Blacks to partake in the subjugation of racism (which is obvious) that has been socially constructed, then this is a result of that racism (again, instigated by whites). However, wielded with the privilege and the power to oppress, whites want to have it both ways and guess what, they have shown us that they can and do want it both ways socioeconomically — and therein lies aspects of it that are quite amusing. This is part of their self-deception.
If you find Black people making fun of the caricatured racism embedded in the concept of whiteness that white people convey to marginalize others then this only signals one thing — white fragility, not reverse racism.
This goes without saying but Blacks could really care less about white people making jokes about their Blackness, they are not that fragile. That is what this means.
They simply persevere it. An education, a skill, an opportunity, a job or career, a home, a family and living life in a good community is what they existentially strive for without wanting to oppress others. They have used white disparagement to build Black pride ✊🏾and persist under far more oppressive, violent actions, along with systemic and institutionalized measures taken against them by Whites who find ways to disenfranchise them from those very same pursuits in life. Here is a tip: a fight for equality doesn’t always look like marches, protests or violence. Sometimes it can be as simple as a joke.
So while the vanity and insanity of whiteness would see this as “reverse-racism”, they really should see it as self-awareness.