I agree with the basic fact
She works for ALL her constituents, regardless how they look.
And this is not a job interview, nor a situation where she gets to set a dress code.
That would be true no matter what the issue was that the meeting was about.
But it's particularly egregious in this case. While clean-cut, well-dressed, unpierced, straight, athletic, white can get bullied too, they aren't the primary targets.
She effectively objected to meeting with the people who are most affected by the legislation the meeting was about.
That isn't just like refusing to meet with black constituents (which would be bad enough!)
It's like refusing to meet with inner-city black constituents regarding crime or gang-related issues regarding their own neighborhoods. There is a possibility that they are precisely the people best able to discuss the issue intelligently.
Intriguing that some of the posters are assuming that the students in question, simply because they had piercings, were not well-dressed and groomed. Because, God knows, you can't wear a tie and a nose ring at the same time.
I don't know if they did or they didn't. But I do note that the stated reason for getting booted was that the piercings disgusted her - not that they were inappropriately dressed.