It’s also not a good picture for this phrase, because both the pot and kettle are black. It makes sense if the kettle is reflective, and the cast iron pot speaking to the kettle only sees its reflection, so the kettle looks black to the pot, when it’s really reflective.
There are two intepretations of the color of the kettle, shiny which is removed from the original expression and black(ened).
The expression is usually best thought of as a kettle calling the pot black because it is burnt on the bottom from being on the fire and the pot points out that the kettle is also blackened - it just cannot see that about itself.
I have always seen the expression less as a statement on hypocrisy/whataboutism and more needing understand your own sense of self before that of others.
The person sending the meme is the one that is saying pot-kettle-black.