Legally, there isn't the slightest basis to the complaint, even on the most extreme possible interpretation of the Supreme Court judgement. A shop floor is not a single sex space, regardless of whether they sell bras or not. This is just hatred and spite, unleashed.
The employee asked the girl and her mother if they needed help shopping. That’s it. That’s all. The misinformation, the insinuations (because the facts are inconveniently benign) are EXACTLY what was done to lesbians in the 80s. This is the product of hate and fear, not reality.