18 complaints in an 18 year career is not as bad as you make it seem when you have someone working in high crime area and are in constant contact with criminals and arresting people.
As a former cop, I can attest that anyone can make a formal “complaint” against a police officer for any reason. I had one for merely pulling over a guy who was weaving all over the road. He didn’t turn out to be intoxicated (I didn’t know what his problem was) and didn’t arrest him, but he still wanted my badge for insulting him.
I can also attest that a police officer who goes through his career with very few or no complaints is a slacker.
And I am not at all defending the offending officer in this case.
I suppose you’re right about the complaints. Hadn’t thought of it that way.