Here in the U.K. stigma around mental health issues has definitely been a big problem. I think things are starting to change now as there have a lot of publicity campaigns around these things, and lot of celebrities and people in the public eye encouraging everyone to be more open around mental health issues. And also more awareness than in the past. But it's definitely still a problem.
I'm sorry you suffered because of this kind of stigma. It's horrible that it made things even more difficult than they already are if you have a mental health problem.
I have recently disclosed my mental health issues when dealing with other healthcare professionals, and they have been very respectful towards me. So I have to say there are some GPs, consultants and nurses in my experience who are educated and respectful when it comes to mental health. I realise I have been fortunate. The idea of healthcare professionals mocking people and dismissing their physical health complaints is just horrible. IMO anyone who does that should lose their job because they shouldn't be working with vulnerable people (probably they would be suited to a job that didn't involve much working with people at all!) I know it does happen in this country too, unfortunately, there was a documentary on TV recently about a mental health hospital that didn't take physical health issues of patients seriously. I won't put all of what was in it because it could be triggering.