Continuity mistake: Johnny's car gets hit, and he comes up and starts banging on the windows. When the girls drive off, the rear window is down, when it wasn't prior.
Continuity mistake: When Daniel threw his Crane Kick in the '84 movie, Johnny fell back and crawled away holding his nose as Daniel jumped around on one leg. But in the opening scene of this episode, Johnny is now prone on the mat as "Daniel" stands there in fighting position.
Answer: Just like in the original film, some guys want that brutality. Johnny in part opens the dojo because of his past rivalry with Daniel and to train a kid that's being bullied. But also, other kids that are being bullied want to join in order to learn to fight back. Johnny is also teaching the Cobra Kai creed (Strike First. Strike hard. No Mercy.") so that's why he opens his dojo with that name and the old Cobra Kai dojo's past reputation is exactly what he wants to elicit.
Bishop73