They are overall incredibly biased against illegal content online and have a huge stake in that. I don't think it makes sense for the same company who produces content and controls a lot of the media to also be the ones blocking "pirate" content.
I wonder how this works with the ISP's that buy internet access wholesale from Bell and Rogers. For example my ISP is pretty small and I don't even think they forward those intimidating letters from production studios nor do I think they would care to enforce random IPs/sites to block. They are just too small of an operation to care/worry about this and wasting money on it. So will Bell and Rogers end up just blocking it on their end and not even giving these wholesale buyers a chance to manage the network?
Overall I really do not trust Bell or Rogers and I do not trust them with blocking things. I really do not want to have to end up using a VPN connected to another country all the time simply to avoid blockades all over the web.
Overall I feel like this just opens the box to further blocking of things not specifically piracy related. You give the government/ISP's a CM and they are going to ask for a meter later.