Per the article, LEO has immunity:

"if they were acting within their scope of authority and the conduct was not willful, wanton, or reckless."

I think this is pretty much the way it works everywhere in North America - sworn officers are ( rightfully ) immune to prosecution while in discharge of their duties. _unless_ their conduct qualifies as malfeasance. Arguably, ( in my mind at least ) arresting people for simply recording the public conduct of an officer already falls into this territory.