Because thats already adressed in the VN itself, also the fact that Tyson does visibly try hard to change and be better.
When you compare how he acts in the VN to how Roswell acted (and still acts to a degree), Tyson shows he regrets it and wants to be better but knows he's going to make mistakes.
However Roswell just continued on just declaring Dave is incapable of thinking for himself and that he's (Roswell) always right and that he needs to make all the decisions for Dave.
Its a very bad look for Roswell. Someone who shows genuine remorse versus someone who just doubles down with a self righteous bluster.
Its why Roswells pretty much the only character that has NEEDED to be rewritten. (The other being dean but thats more just to clean up and make him SFW)