From the video I saw of this on FNC this morning, the “pepper spray” didn’t seem to bother them much. The fleabaggers acted as though they were being sprayed with a water bottle. Just my observation. “Stinging” normally gets some type of a reaction.
I look at this as the police giving them one last chance to disperse. I don't think they wanted to arrest all those people and thought a shot of OC would help. They did get a couple to move.