I have to be really honest about this, it's not only their fault, everybody that ports from IV or any other gta game are probably frowned upon by rockstar or any other company. Tobehonest if i were a game company i wouldn't like that people take models from my game created by my coworkers being converted to other games. These models are not free!, they are created by an individual or team who gets payed to do the job.
In short terms it's like releasing an unlocked model, people who made it wouldn't like if somebody edits their model or converts it to another game. The only models this doesn't apply to are scratch made models since they were made for free.
That's why i've stopped releasing models from other games