I'd venture a guess the reason is because many WDW fans are also fans of Universal (and of theme parks in general). Sea World, USF/IoA, BG,
Legoland, etc. all play a part in many people's Orlando vacations. It IS possible to enjoy the thrills of Dueling Dragons roller coaster and appreciate the state of the art technology/immersion of Forbidden Journey without detracting one iota from our love of WDW.
The ONLY real comparison of the two parks I see posted here with any regularity concerns the fortune WDW spent on
MDE/FP+ compared to money that Universal spent on adding more new & amazing attractions for guests to experience. I'm looking forward to visiting Universal in the future, not to teach Disney a lesson, but because I want to experience all of those new amazing attractions that are being added.
I'm already looking forward to 7DMT, and when Disney adds more new (and much needed) attractions, I'll be looking forward to those as well.