By that the commenter means (I guess) that to be pro-union in the United States of 2016 (where obviously things work swimmingly well for wage earners, without the union-enforced wage and job protections commonplace in other countries) is sufficient grounds to have one's psychological well-being questioned. Indeed, it may be a sign that one is suffering from a bona-fide psychiatric disorder.
Yes, I thought the meaning of obsessed was clear. The poster was referring to people who are preoccupied with (presumably, `others'`) community contract negotiations.
