Because the security shown on all the videos don't appear to have those ready. That sort of gear isn't typically equipped. So its sort of irrelevant to what p

Because the security shown on all the videos don't appear to have those ready. That sort of gear isn't typically equipped. So its sort of irrelevant to what police who were suddenly asked to hold a door from a violent mob. With hindsight they should have had teargas ready. But they probably didn't expect the President to direct a mob to capture the Capitol.