Well maybe they're ok with that? They want browser diversity. Getting Microsoft to use a new engine is better for diversity than if they just used chromium like now.
Oh no no no. We don't need microsoft contributing anything into this. They will mess up everything and push their agenda.
Google was almost killing Go overnight because they wanted more user data from people using the language.
If your goal is browser diversity, this would take an ecosystem of 2 browser engines and turn it into an ecosystem of 4. That seems in-line with the goal of browser diversity.
Having 4 (or 3.5 more realistically) browser engines where 2 of them weaponized against its users doesn't change things.
Instead, we should have 3 (or 2.5) browser engines where only one of them is (and can be) weaponized against its users. This is what brings diversity and change.