In looking for a friend, you need to be giving to them more than taking from them. If you only take from someone even over a friendship, they will eventually shun you.
You were right all along in this instance. Knowing that you cannot "trauma dump" on people, especially new acquaintances and expect them to stick around. They won't. And that they are likely to warn others in the process to stay away from you when you frequent the same place with the same people. Which appears to be obvious from your own account.
Change your behavior by focusing on giving to others, instead of always taking from them. You might eventually find that people begin to see you in a different light when you stop thinking of only yourself and your problems. In this respect you can start here. Instead of endlessly posting about your own problems, consider addressing the issues of others here. To be a friend to them, to be of help to them in any way you can. To give, rather than take.
For better or worse, the world is full of "givers and takers". But if you should always take without even thinking of giving back, it will always catch up with you, and people will and do ostracize you. And no, it's not easy. However it's still a must if you truly want to remain in the good graces of people in general. To suppress your urge to tell people about yourself emotionally. Stick to simple things like what you might have in common with others.
Learn to give, and try to set aside what you are accustomed to taking from others. And in doing so, you may eventually begin to understand the efforts of so many people here who have tried for years to help you in earnest. Of all people, it is we here who have not shunned you.