“Microsoft said that Bing data is protected by stripping personal information from it and that only certain employees could access the chats.”

If they’re trying to understand how interactions influence the output, it makes sense that they would study the interactions. I don’t think most people would object to this if they believe all identity and personal information have been removed. Of course they should also be more transparent about what they ARE keeping related to identity and whether someone identity could be constructed from the data they’ve retained.