I haven't had the time to learn it so I wouldn't know whether or not it is good or bad but overall I think the majority of cubers use CFOP then maybe Petrus and Roux.
I would think people aren't being
mean. It's just there opinion. Whether or not you would listen and make a fuss about their opinion is another matter but I think Petrus seems to me like it could be a good method in terms of getting good times. I remember
@PetrusQuber getting 12's and 11's on his channel which is better then me using CFOP by a long shot.
However, opinions are opinions and Petrus may or may not be a good method.