Admins own the platform and they totally have the right to set whatever rules they want. No one is debating that. The thing that people point out is that despite admins having those rights, they might be exercising those rights in a way that people disagree with (for whatever reasons), which might ultimately lead to the demise of that platform.

I, personally, find your reasons against the ham-fisted approach they have been taking to be very compelling. While r/The_Donald ban was probably warranted, and I have nothing against that ban, the overall vibe of reddit definitely feels like it has changed over the past 10 years. It feels like it went from "user-driven content under the umbrella of basic global reddit rules" to "heavily-directed content that admins seem to approve of or content that they cannot justify getting rid of just yet (but probably will soon enough)".