Do people who fear negative thoughts about them, perhaps being a member of a minority, tune into the collective unconscious and then experience a tidal wave of negativity from the thoughts of that type which have accumulated there?

This is very much a factor in human happiness and a source of discouragement for many. When one goes looking for trouble one will find it. If it is not right in front of them, it will be reachable via the thoughts themselves and their content being a match to what is in the collective consciousness, and that will be accessed automatically and will echo back to the thinker. So if one is fearful of judgment, criticism, projection, or exclusion based on prejudice, that thought will find its way to the collective unconscious and be met by a complementary repository of judgmental prejudice. And so the echo in response will be a stream of dark and ugly thoughts that represent the worst fears of the person who is concerned about fitting in, and who is worrying about being singled out by the existing prejudice in those around them and people around them. This is one of the ways in which cultural negativity persists because it exists indefinitely in the thought-plane and is not readily healed because no one is seeking to do this. This too is a hint for you. With an accumulation over, in many cases, years of negativity streaming constantly into the collective unconscious it becomes a formidable challenge to exist without having a sense of bias in the air, so to speak, which is really just an awareness that people out there have thought dark thoughts about them and their status as perhaps, a member of a minority or other circumstance where the may not fit in readily but meet with skepticism, or criticism, or a negative reaction of some kind. When prejudice is deeply entrenched and goes on for many years the accumulation can reach extremes where even following a change in laws to liberalize things to reject prejudice thinking as being a legal reason to limit the reach of individuals those ideas, by virtue of still remaining in the collective unconscious, will be sensed by new generations growing up who have that identity and while no longer formally judged and excluded by virtue of the protections afforded by new laws giving them equal rights for example, will nonetheless feel the sting and feel every bit as excluded because they are being bombarded by all of the judgmental thoughts, and rejections, and hatreds of those who came before and left their mark. This is a long-term problem in need of a solution and there is much that can be done to bring healing for this. This is best done through collective agreement but can be done by individuals, as well, working purposefully to make changes.