I dont think that is true - for the flights Jet2 offer, why would anyone fly via a hub? They want direct flights and where they are not available from GLA, the convenience of EDI to West of Scotland passengers helps this (it is on the right side of the city for one). I'd imagine there are also some passengers that would use GLA over EDI for a direct flight but in general GLA is harder to get to if you don't travel by car and is on the wrong side of the city to make it simple for East of Scotland pax.
Its your choice that you wont use EDI out of principle and its admirable that you support your local airport by always flying from there but i would suggest that the majority will actually seek out a direct flight wherever possible (certainly to any of Jet2's destinations) rather than have to connect in London for example.
This is of course different for long-haul flights where a connection is more acceptable.