I don't know about the hate for the 3x systems, I guess it is just a lot of people want to optimize their setup because triples are redundant.
I will be changing my drivetrain (because it has to be changed) to a 2x10 because I never use the largest cog in the front. So the problem with it is that at speeds over 35km/h I could shift to a smaller cog in the rear but that causes chain to rub against the front derailleur cage so I have to shift at the front and that makes cadence a lot slower and requires more power.