Asking "what would you do" is inherently flawed. It calls for speculation based on far too little information, and leaves the subject without the benefit of being in that situation. I can think of many reasons to continue and many reasons to divert, and can tell you that I would use my best judgement given all the factors in consideration at the time. Those factors would include, but not be limited to the nature of the situation, the threat posed by the subdued individual, the fuel state, weather at destination and alternates and diversionary fields, aircraft performance, company needs, safety of flight, extenuating circumstances such as maintenance issues or inoperative equipment, political considerations, etc.
While the flight attendants and others on board have important insights and information, they don't have the full picture regarding the flight, nor are they in posession of all the facts. Nor are they in charge of the flight; that's the job of the pilot in command.
Should the captain in this case have diverted? I can't say, as I wasn't there. One may expect that the PIC will take all the information into account; not just that provided by the flight attendants, but all the information. Decisions to divert or proceed may be impacted by many criteria; the combative passenger is but one thing to consider.