Or because they were tricked. eg. LinkedIn’s “Connect with your contacts” onboarding step which sounds like it’ll check your contacts against existing LinkedIn users but actually spam invites anyone on your contact list that doesn’t have an account.
I also see the shenanigans of adding new 'privacy' settings and setting them open by default. Another typical Microsoft ploy by the way.
Previously they’d take your LinkedIn password and try using that to log in to your email account to grab your contacts.
And I kinda get it, some services external to your bank can help you manage your finances etc. But it's why banks should offer APIs where the user can set limited and timed access to these services. In Europe this is PSD2 (Revised Payment Services Directive).