Its basically the same distance to go to SE Asia from the East Coast as it is to go there from the West Coast. Given that the RCN is in no hurry to move assets. There is far more space on the East Coast (especially as they just bought more space as
@HaroldBloggins just mentioned)
As far as more East Coast frigates recently, its not a shortage of assets on a coast its part of a deliberate policy, Canada's Asia policy states there will be three ships a year in the Pacific. The Kingston class are the ones doing the NATO deployments assisting with the standing NATO mine countermeasures flotilla (or whatever its called).
So yah, more attention to OP HORIZON (SE Asia)/ OP NEON (Korean peninsula) than OP REASURANCE (NATO) as per gov't direction.