Because you’re using an external device to extend the capabilities of the port. It can’t do that without the dock, so now you have two things to carry around.

Maybe that's what the previous commenter meant, but they were bemoaning the number of ports, not dongles, etc. Even then, if you are using those ports, you are already carrying around extra accessories/dongles which might be replaced by the dock (or in my case, moving between stationary docks).

If you look at the comments on this, there are two distinct camps of people who will never agree: those who expect their laptop to be a self-contained unit that doesn’t require anything that wasn’t packaged with it to meet common use cases (which requires more ports), and those who are okay with docks and dongles and adapters.

Sure, and other commenters are pointing out that manufacturers are serving both groups.