Core teching is something, that was designed for faction to be used in unlimited numbers. I agree about limits for doctrine units, but basic stuff (snipers too) should be limited only by popcap.
I agree that it's not something that should be overdone, but technically non doctrinal limit allready applies to another unit - The KT.
And yes, I know that's an entirely different ball park, but I do feel like some things reward lazy play that let's you punch above your weight without much effort.
But overall I see the point that this argument could be made in many instances.