Nobody is arguing for overcomplicating things, and it's true that a lot of projects out there are in fact overdesigned. However, there are also non-trivial applications out there, and front-end can in fact be complex in such apps. For example, I worked at a hospital at one point, and my team built an application that allowed multiple users to work collaboratively on shared documents seeing each other's changes in real time. That's a kind of app that is non-trivial, and where there's plenty of legitimate complexity to be found both on the frontedn and the backend.