Someone is saying it VIOLATES regulations. That's cut and dry  

getting the idea you may be offerring the idea that person who goes over 14 under Part 91 can work another 2-3, maybe 5 hours. 

Let's say that individual got up two hours before reporting for duty, did his 14, then some Part 91, on behalf of his employer, or possibly at the direction or insistence of his or her employer, and, voila, there comes some incident or hopefully not an accident.  Don't think the FAA will not look at fatigue and possibly operating in a careless or reckless manner as a result, and they CAN make it stick.

Just because under this rule and that one we think some things are just fine that may not be the case.  Ya have to look at all regs with due respect of what is undertaken.

Whew.  Apologies, way too long.