This is a big deal on here and people are so against it but dont really understand what the advantages are of it. But since you asked nicely I will divulge
There are fitment and performance reasons why tires are stretched.
First I will go over the fitment. Stretching a tire stretches the sidewall in away from the fender. This allows to run a wider or more neg offset wheel withouth the tires rubing on the fender. Depending on the setup lets say for example you have wide wheels but with thires they will rub on the fender. U can either run a widebody kit, pull your fenders or run a stretched tire with just a rolled fender.
Now for the performance aspect, A few performance cars come with a stretched tire from the factory like the BMY M3. Running a stretched tire allows for a very predicatble break away point allowing for the car to be more contrallable around a turn. If you get really radical and stretch the tire more you still keep the predicatbility but your threshold of traction is lowered. Thats a big reason why drifters stretch tires.
Another thing that people are commonly mistaken about is contact patch. Lets say you have a 10 inch wide wheel and you run a 245 series tire. If you run a 255-265 tire the effective contact patch has not increased greatly. Because the 245 is stretched over and has a similar contact patch to the other tires.
Other things that I probably failed to mention. But people get on the bandwagon and bash it because they dont understand why its done
