If someone is ignoring you, they will probably not stop ignoring you to tell you why. That's what "ignoring" means.

Mind you, perfect 'ignoring' isn't something people are especially good at. Many people will answer that question. If you happened to be interested in what such people may tell you it could be worthwhile to ask. The private vs public distinction also matters for many who are aware that giving that kind of public criticism can tend to negatively impact the reputation of the speaker as well as the recipient.