King Cobra - S3-E6
Factual error: Flashback when Kreese is in Vietnam. His captain, as well as other officers at their base camp were wearing modern uniforms, wrong for the time. (00:01:05 - 00:01:29)
Factual error: Johnny gets a personalized license plate that reads "cobrakai", which is 8 characters. California license plates only allow 7 characters.
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