There is a very, very big difference between a) observing what appears to be self-sabotaging, from the extremely limited information we have here, and commenting on that from our own individual perspective, and b) saying "I can't help but feel there is some kind of borderline element going on here", which is an assessment and a diagnosis which have to be made within professional psychiatric discourse.

If you read threads here you'll see that people call each other out on nonconstructive behaviour all the time, and point out what we (from our narrow points of view) think we can observe. It is not the same thing as offering professional diagnoses.