i dont think they not doing it for any hate or bad reason, Source 2 probably breaks the whole game, so u need to be really careful how u port it, and at what time.
Its the update im wishing for, and im waiting for the most, cuz it will bring up the hype CS:GO needs and deserves, and i rly hope Valve promotes it the way it deserves with a hype trailer or cinematic or whatever, and i know they know how to do these things REALLY well, WHEN THEY WANT.
What i think is that they gonna showcase Source 2 with 2 new freshly ported maps to the engine, to kinda "showoff" what the engine is capable of doing. Those 2 maps, office and mirage. BUt its all a mystery, and valve loves playing with this. They watching how community reacts. For sure.