No one is arguing against this cruise in a vacuum. If Disney had offered it in 1990, folks might think it odd, but its unlikely they'd object very much.
What the "if you don't like it, don't go" folks rarely acknowledge is that people object to these upcharge activities because they are representations and intensifications of several very negative trends that are afflicting WDW. In a nutshell, they are representative of
1) the use of WDW as a cash machine, with constant price increases, attraction and entertainment cuts, and (until recently, at least) very little spent on improvements
(more troublingly) 2) the increasing stratification of the WDW experience and the sense that guests are increasingly categorized as first-, second-, or third-class. It's infuriating, particularly given the rampant price increases, that WDW is making it more and more clear that certain guests are better than others.
It would be great if, when folks defend these upcharges, they addressed the broader context as well.