Yes Cam has rightly received received criticism for sulking on the sideline during losses and pouting during press conferences after losses, his SB presser being an embarrassing example.
However, the meaning of "cancer" applied to sports is well established as a player who causes discord in the locker room and is disliked by players and coaches. Cam has always been well liked and well respected by players and coaches, a fact reported on consistently and extensively for the past eight years here in Charlotte. Unless you're going to claim to be using your personal definition of cancer and not the one literally everyone else uses, you're dead wrong here.
I slightly misunderstood your "didn't do dick" comment, I was thinking you were talking about his MVP award not just the SB performance. Fair enough, no real argument there.
As far as Newton being overrated, I'd say that's a pretty subjective term, I mean overrated by who? I think Cam's strengths and weaknesses are pretty well agreed upon at this point. He's a strong-armed QB who sometimes struggles with accuracy and overthrows. He's also a mobile 245 lb QB and a serious running threat. NFL MVP, Offensive POTY, laundry list of passing and rushing records (seriously just go to wiki, the list is ridiculous), hey if you want to pull overrated out of that go ahead I guess.
I will concede however, that Cam's fashion choices are unfortunate, and he damn sure pussed out on that SB fumble, he's going to have to live with that one.
On another note Josh Allen has been surprisingly impressive, that's a different subject.