Actually, it is a Canadian network - if you see FX on any Canadian cable provider, it is FX Canada, licensed from Fox, owned and operated by Rogers.
The US FX channel, like any number of well-known US cable channel brands, is not licensed by the CRTC to be carried in Canada.
And as far as answering why FX Canada is not on Bell - well, Bell in general as a BDU doesn't appear to have the best of relationships with Rogers as a content provider. There is still no West coast HD feed of CityTV, Omni 1 & 2 HD are still not available on Bell, and there is still no agreement in place for the carriage of FX.
Anyone else here have any examples of Rogers content being underrepresented or unavailable by Bell?