There’s 2 reasons that can happen.

1. It’s not actually overcomplicated, but the people saying it is haven’t thought about it hard enough to realize this.

2. It is overcomplicated, but it’s such a tangle of complexity that fixing it would require the people pointing out the problems to basically do it over from scratch.

#2 is usually the result of a very experienced developer being overwhelmed by the amount of complexity coming out is the vastly larger amount of inexperienced developers around them. It’s much easier to add complexity than it is to fight it.