Are you someone seperately aware that an arrest warrant was obtained, or that this man was arrested? I have seen no indication that either of those things occured. He was not arrested (as best I can tell), and their was no arrest warrant obtained.
While what the technical implications of detention during the service of a search warrant can be very complicated, and highly dependent on circumstances, the Supreme Court held in Michigan v. Summers, 452 U. S. 692 (1981), that...
"Of prime importance in assessing the intrusion is the fact that the police had obtained a warrant to search respondent's house for contraband. A neutral and detached magistrate had found probable cause to believe that the law was being violated in that house, and had authorized a substantial invasion of the privacy of the persons who resided there. The detention of one of the residents while the premises were searched, although admittedly a significant restraint on his liberty, was surely less intrusive than the search itself."
"Yeah, I'd sue the hell out of these cops (actually, their employer), and take this case on contingency. "
You'd lose.
Based on their treatment of the owner, i have to assume that they had an arrest warrant. If not, then it is even worse for them that they roughed up a man without probable cause to even be making an arrest. As i said, i’d take that case. I am very careful with the cases i take on contingency. I have to believe in them absolutely. I have never taken a false arrest that i lost, and i would take this one, based on what we know now. Maybe you would not. I would say, see you in court.