I think the very defense you're using is the problem though. It's fine if nobody uses the competing browser for work at Google. It is, however, pretty standard to have automatic tests for performance and functionality, and these need to be cross-platform. Having insufficient automated testing for Firefox to catch these sorts of issues is a structural, anti-competitive bias. Especially when these things clearly don't happen with Chrome.

Couple that with the article's documented case of using a deprecated API from Chrome that's unsupported in FF. That's bias in the design, and that's something that leadership is either not catching, or making a conscious decision on. I'm sure it's couched in some statstic about which monetizable users are impacted or something. But at the end of the day it's an organizational, structural bias.

And that's not to say this is necessarily illegal. I honestly wouldn't know. But I think you made a straw man to attack. The allegation isn't necessarily that there's an organization wide conspiracy of evil Googlers. Just that the organization and culture is designed to benefit Chrome and disadvantage Firefox, and that's happening regularly with user-harming effects.