As I said earlier, fans of Disney parks can take their rivalry to spiteful levels. This happens regardless of the park and it's actually really stupid. Some overzealous Disneyland fans might diss anything that isn't "Walt's park", whereas you might see a reactionary comment from a WDW fan as well. Disneyland fans have every right to cherish the originality of their park, WDW fans have every right to cherish the uniqueness of their own resort. I don't see a reason for one to diss the other when there's greatness in every Disney resort on earth (and for the fans who do it, they're only doing themselves a disservice by refusing to visit and enjoy them all). I'd still be inclined to wager that Walt himself would have been pretty upset that fans were creating disrespectful, bitter, and frankly immature and pointless rivalries among his parks. I'd also wager that when planning WDW, he wished for people to enjoy it, not to fight like mad dogs about what resort was superior.
Now all that being said, I will say that I don't get the feeling that the author intended to insult any of the parks or their guests. I certainly get that people can do that, but here I get the feeling it was more an attempt at rhetoric (perhaps a poor choice of words on their part) in order to get a point across. I'll cite WDW1974 here for instance, he uses a lot of sarcastic comments that might sound insulting to people who don't know him and his style. But they're actually made with a respectful undertone to them in regards to Walt Disney and the parks. Like mocking how current leadership mistreats the Disney legacy by sarcastically referring to Walt Disney as "old dead guy Walt". That comment you can take however you like, though it was made as a reflection of how many Disney leaders view the man and his legacy they're in control of.
The point of course being the homogenization of the parks, a fair complaint that I would agree with. Magic Kingdom shouldn't be overly like Disneyland, and Disneyland shouldn't strive to be exactly like MK. Heck, it's done even within the parks themselves, such as removing land-specific merch in favor of generic items sold park-wide. Current leadership has certainly done a bad job keeping the resorts unique experiences. Again being unique was what made Epcot so wonderful (heck Animal Kingdom as well had it been a fully realized entity from its concept).
The article has plenty of great points, ones I agree with. But the points do work fine without making statements that could be misconstrued as an insult. I'll also say that probably the biggest insult ever made to ANY of the Disney parks isn't something that any fan has said. It's the simple treatment that modern leadership gives to them.