Nvidia does this all the time. If anything, I’d like to see more games focused on AMD graphics, it’s a tactic that AMD as a company has been getting whomped by.
Ideally, though, there would be better support for all graphics platforms, though.
I don’t think it’s deliberate, per se, but Bethesda was clear about who they were partnering with, long ago. If a graphics company is trying to help you optimize for their platform, they aren’t going to be stressing abouy the impact on their competitors.