I dont think thats the case at all. I am not sure what qualifies as a minority, but the union where I work has been instrumental in ensuring that disabled employees have access to tools they need to do their job and the support they need. They help when restructuring brings redundancies, they negotiate retraining packages for people etc.
You have fallen into the Us v Them trap that benefits employers. Your employer does not see you as significantly different to any other employee, even if you think you are. You have more in common with the other employees than you do with mid and senior level management.
Consider it this way, if you died on the way into work tomorrow, your colleagues would mourn and miss you, your employer would be typing up the job post whilst wondering if they could get someone cheaper this time.
I genuinely think you have some serious misunderstandings about what a union can and does do for its members. I don't know of one union that would prevent you from negotiating your own contract or terms and conditions. What you will find is that the bare minimum of acceptable terms has already been agreed with the union so you are starting negotiations 1-step up from where you would be without them. What this means for you is that you aren't using some of your powers of persuasion to ensure you have e.g. 14 days leave per year, you can now use that leeway to negotiate dental or medical, or whatever else you value.
I would just point out that employee unions are pretty strong in Europe, not over powered, but we have maternity pay, sick leave and generous annual leave allowances. In the US you dont like unions, have woefully inadequate annual leave, sick pay, maternity pay etc.
"Socialism never took root in America because the poor see themselves not as an exploited proletariat but as temporarily embarrassed millionaires.”
In the same way it seems like US employees don't see themselves as employees but as business owners/managers who haven't quite achieved their position as yet and a union would be detrimental to them when they are in that role even if it would benefit them right now.