Imagine you have a computer that’s been compromised by malware. What do you think the search engine will be set to? Not Google, not Bing, probably some third party one that has ads and malware. Changing that to Bing would technically qualify as a repair.
They could easily improve this by just adding a list of common reputable search engines, and adding those to an allow list.
As a Linux aficionado, I appreciate you trying to bring an argument for Windows in good faith and a potential way for Microsoft to improve it. This is even if steering people to Bing is Microsoft's intention with this move so they are unlikely to improve it in the way you suggested.
Since forever, Microsoft-affiliated products are often the only things that get the "trusted" label within the Microsoft ecosystem.
Glad you had something useful and helpful to add to the discussion. Have you ever in your life heard of “playing devils advocate”? Read a book some time.