Google blocks ads from their competitors. [1] In the article, they state it’s because those companies are not following their standard, and are using too many resources. (Which they claim negatively impact device performance through metrics like battery performance)

In comparison, Microsoft implied in their advertisement that their browser is safer than Google’s because it has the “trust of Microsoft.”

[1] https://blog.chromium.org/2020/05/resource-heavy-ads-in-chro...

I won’t defend user hostile actions regardless of where it’s done. Google is a bad actor when it comes to abusing their position, so is MS.

I don’t however think there’s a strong argument to be made that MS is modifying the website unless they MITM it. It’s well within their right to make their browser display something they want it to in a specific situation.