It was the CEO of Disney and it happened after threats from the head of the FCC.

Edit: to clarify, the CEO of Disney caved to pressure from affiliates owned by a Nexstar who are actively petitioning the FCC to relax media ownership rules so they can buy more affiliates than the law allows.

Not even just that, the FCC chair directly threatened ABC's broadcast license if they didn't do something about Kimmel.

If that's not infringing on first amendment rights, I don't know what is. The right will of course support this; they tend to treat the constitution and laws as flexible whenever their ideology requires it.