If working at McD's can be stereotyped with the phrase "flipping burgers", I propose that packaging things at an Amazon warehouse be called something like... "boxing dildos".
It's ambiguous, though. They could be complaining about the frycooks making as much as them, or about the frycooks not making as much as them. You'd have to look at what else they posted to see whether they're generally pro-labor or not. Or ask them what they mean by their tweet. Both of which are made difficult by the username being blocked out.
It really isn't ambiguous at all, imo. He's clearly saying flipping burgers isn't skilled labour. Like that's literally what the sentence means, as he's comparing flipping burgers to "skilled labour", which he wouldn't do if he thought "flipping burgers" is "skilled labour".
He says he'll be "damned" if what he says are unskilled worked at McDonald's would be paid as much as him — who identifies as someone doing "skilled labour"