NY Mom – good example. You are right, there is no point of a support group if the audience is unsympathetic.
The group would only work if the members were aware of where each one is holding in terms of tsnius observance. So if Member A never wore a sheitel and then posted what you describe, the other members could say hurrah, and many more. But if Member B who always wears a sheitel posted it, the other members would be unimpressed.
Such a group might (understatement of the year?) not work in the CR.