Rubbish. Utter Tosh. The only accurate thing there is "stocky," which is part of the breed standard.
Pitbulls aren't even thuggish, never mind MC's. Maine Coons are traditionally laid-back, mellow family cats, and also have a tendency to clown around. They're also fabulous mousers.
I have known many thuggish cats who were prone to attack, but it had WAY more to do with their treatment, upbringing, and experiences than their breeds.