Apart from the search engines being both shitty, here there's nothing wrong

If you installed an extension to use bing search, what you want is to use bing search, not Google. So of course the extension has to say "don't switch"

There's also a good point on chrome's side. There's extensions that will switch your default search engine without your consent, so having the possibility to undo directly is nice.

Another way to see it, would be to switch chrome for firefox, Google search for duck duck go, and bing to qwant. Same story, but no shitty companies clouding judgements