All I can say is that he must have mellowed later on. I grew up in Wayland, lived there from 1955 to 1979. Back then Cook was universally hated by both the towns people and other cops.
This quote (taken from the link above) typical of his mind set back then
"It seemed like society was going through a readjustment after Vietnam, and we had a lot of young people who were upset with the government," said Cook of his first years as an officer in the early 1970s. "You could either be on the side that was rioting or be on the side of law and order. I gravitated toward the side of law and order."
What Cook said he experienced on the Wayland force in those years was a confrontational generation which included a rapidly growing drug culture, youth groups organizing against police, and violent attacks on police with bullets, razor-tipped tennis balls, and dynamite.
"That was the mindset up until the end of the ’70s," said Cook. "Police would be shot at in Wayland. I knew another officer who was ambushed and attacked by a group after they gave him a phony distress call. The Burlington police station was even dynamited.
"It was pretty much understood back then that if you were responding to a noise complaint, you put on your face shield and grabbed your night stick," said Cook.
Fortunately, said Cook, that level of confrontation in Wayland decreased by the 1980s when the Vietnam generation became older and "slowed down a little bit."
"In the 1980s, when we saw a couple hundred people at the Cochituate ball field, we knew they were there for a baseball game, not for a riot," said Cook.
I spent many,many nights at the cochituate ball field. All the other cops would come by and check up on us, but rarely did we have any problems with them. But every time Cook came by it was a big hassle. He was always looking for a confrontation and was so disliked, he usually found one.
As a side note, I received my first LTC in Wayland when I turned 21 in 1973 (which I have had ever since) so obviously I had no problem with any of the other cops in town.