The answer is ‘behavioral isolation’. It is a form of
sympatric speciation - which occurs even when
species live in the same habitat. In this case,
the individuals in the population are isolated by differences in mating and probably different mating rituals.
Fear is a barrier as people fear being judged for things as there might be a stigma attached to it. When people are judged their problem isn't solved and instead worsened and they will feel compelled to keep their problems to themselves.