Without the specific facts is hard to pass comment. However, on what was presented in the footage, the officer was completely justified in utilising the TASER (i.e. violent resistance or confrontation occurring).
Most of the time I find that those who generalise in relation to the police (corruption, brutality etc) usually attack those who generalise in relation to cultures, minorities etc, and generally know noone within the organisation. I'm also assuming that these persons who so vehemently despise the police and their overtly authoritarian role, particularly the extreme libertarians, will look elsewhere for assistance when they encounter a situation that usually requires the need for police attendance/action.