No it is not negative to be on TPB, it is just that everytime TPB announces some guest will be on a bunch of negative comments start being posted by TPB fans. The first star on the show was Alex Lifeson from RUSH and you should have seen all the negative comments on Showcase, "how can TPB have stars on the show, the show has jumped the shark!" Of course most people ended up liking that ep and Lifeson.
Many people still bitch though, just like they did last season when they heard Sebastian Bach would be on the show. In general there are a lot of stars, many of them rock stars, that would love to be on the show.
As for your other question the show is popular in Canada but there are some people that don't get it, they are the people who haven't given it a chance.