You are not in a position to determine if someone is "pretending" to be a street tough or actually IS one, sweetie. The fact you aren't willing to admit, or accept that talking shit could lead to retaliation (regardless of what you think about that retaliation) tells me you're not living in reality, or just pretending not to be in order to ride a moral high horse on a karate forum about one dude sucker punching another dude.
You don't even need to be a "hard boy" in order to understand these things by the way. I never was a street kid but what I did learn early on was common sense.