Would you feel the same way if she added a banner that suggested her fellow employees exercise their 2nd amendment rights?

Bad faith argument aside, informing people of the rights they do have is not really having a political stance. Those rights exist regardless of what one personally supports. Obviously, this holds true for USA's 2nd amendment rights as well as any other provisions granted by the law.

Companies have active interests in suppressing this sort of information, and put forth efforts to try and convince people that literally stating the laws of the country that one resides in is somehow pushing a political agenda.

It was the parent comment's language. I was more taking issue with the "cork board" metaphor