I agree that punching the gallery owner regardless of gender was a despicable, criminal act and was wrong. But I don't think the gallery owner should be so surprised at the reaction she has received over displaying art that invloves issues that are so devisive to the country. It doesn't matter if she is not taking a stand one way or another, by putting the art on display she is by default taking a side and making a statement.
Another case in point was the conservative Denver talk show host who was pretty far to the right and got murdered for his views. Not a proper reaction to someone elses views but I guess it comes with the territory.
In a perfect world, people who disagree might come in have a cup of tea, voice their displeasure but respect the gallery owner for displaying the art and the artist for creating it. But it ain't no perfect world. Yes getting punched in the face was very, very wrong, but on the other hand, if you get in the middle of such a volatile issue don't be surprised if someone does punch you in the face.