What movie did you just watch?

[Ton]

I can't follow the logic of different taste == no taste

That's because that isn't what the argument usually is.

Different taste =/= no taste (or bad taste), not intrinsically. But bad taste is still intrinsically different than good taste, so there is something of a minor overlap.

I don't think it's bad taste to not like The Godfather. It's a product of a different era of moviemaking when the focus was on other values. It's not something people are used to these days. Granted the Italy segment slogs on a bit, but that ending and all of the complications leading up to it are fantastic. It's a tragedy about a family.
So it's not bad to dislike it, but I will say unflinchingly that you're wrong in doing so.