I don't know what makes you so sure. Supposition on your part? A poor one it would seem. I fear no one. And the only one's I've met that are capable of 'kicking my @ss', I am fortunate enough to call friends.
I don't pick on humans that is correct. But when they attack me and the situation warrants it, I respond with maximum violence. At that point my life is worth more than theirs.
Animals are a different issue. If a dog was repeatedly harassing my kid, in my presence, at the urging of its owner, I would have no problem dispatching the dog. Physically or morally.
"Tough guy"? Maybe so. Maybe not. I am a "big guy" though. And I am not someone you want to mess with when my family's safety is on the line. That's not bluster. Just a fact. Take it or leave it. I don't care.