Having seen the second clip, of the other women, also dressed in red, there is no way he didn't know that there was a Greenpeace protest happening. Hammond had been asked to stop speaking whilst the protestors were dealt with, all in the room knew what was going on, the whole area by the doors was full of women speaking, demanding changes, and a lot of security.
Field was angry. The way he first contacted her, hand to her chest, straight arming her off, onto the pillar, is not how a man would normally handle a woman in a thin, armless dress. He was simply angry... and he reacted like any angry, bullish man does. He literally manhandled her out. That was a man who has had some training in self defence using it to overpower a woman and remove her, as though she were a much larger, more violent threat. It looked to be a disproportionate action.
The hand clap wasn't applause for him though, was it? It was a slow hand clap, the sort used to show displeasure and was probably aimed at the Greenpeace protestors.