>>55461805The thing about any franchise is that people will tend to latch onto things that their franchise otherwise lacks if there's a general feeling of dissatisfaction and resentment.
For Pokemon that's
A. Creativity
B. Difficulty
C. Mechanics outside the realm of single battles where you knock the other team out and win
D. A more serious plotline and focus on story
Colosseum fits into that mold for a lot of people, irrespective of the actual quality of the game being pretty poor and jank even by the standards of when it first came out.
Pokemon fans are just not very smart (due to being very physically or mentally young most of the time) and don't tend to go outside the boundaries of Pokemon, so they get blown away when things happen that break their preconceived notions. Even moreso when the franchise does away with said things in future entries, so that they can then cry victimhood or lazy development processes even in the possibility newer games are far more complex and well done packages.
If Gen 10 looked gorgeous, had no performance issues, a very well liked Pokemon roster, etc. you'd still have these people.