Until the last couple of years, the manufacturers all used their own electronics, but now all the bikes must use Magneti Marelli electronics and must figure out how to use those APIs to control spin and throttle. Last season, Yamaha couldn't get this right with its chassis, and its riders couldn't make the tyres last the race with decent grip.
Yes, MotoGP allows traction control. Like all technical innovations it has led to a change in riders priorities and skills. Some people dislike it, but overall it's not accepted I'd say. Personally I've found it interesting to watch riders adapt there riding style to the new technology.
Yes, MotoGP uses traction control. I can't speak for anyone else, but I don't really care. Like F1, it's a prototype class, so results are a combination of the rider and the machine.