I mean, I'm not going to defend Onedrive (aside form saying it "mostly works just like the rest") but how is it the app or the vendors fault that someone send you a link that required an account to access? There is an "anonymous access through this link" sharing option that does work as advertised.

This works the same for Google drive and most of the other services. The problem is that most users don't understand that the link they create still has access controls attached (that they can change).