Well shiver my timbers. The finger of blame gets pointed back at the flight deck (along with a bit of personal abuse- but I don't think that is productive!). So let me ask you both- you say the Parking Brake was not released when you commenced pushing, hence pin breakage? What sort of operation is that? The pilot asks for pushback, the ground operator asks for Park brake release, the pilot confirms Park Brake released, pushback then commences. What sort of procedures are you using?
I have to say in all my career, I have seen a constant procession of tow incidents- far more than ever caused by pilot collisions. From pushback/tow damage such as with this particular aeroplane that will cause it to go out of service for approximately 6 weeks, to aeroplanes being pushbacked into other aeroplanes, to maintenance apron damage and damage going in and out of hangars. Add to that litany constant baggage loading/service vehicle collisions with aeroplanes, and it appears to be a frightening toll on the industry. Maybe time for proper safety procedures to be drilled home, with several high profile sackings of such carelessness? I watch some of the empty towing operations now and I don't like what I see. Pilots manage to manoeuvre these massive aeroplanes around airfields, even without being able to see the tail or the wingtips, quite safely, with accidents incredibly rare. Why are so many aeroplanes damaged by towers? There is no excuse for a tow team to fumble a pushback where the brake is still set. That is not down to the pilot!
The expression I would use is 'cavalier'- it sounds a bit better than 'cowboy'.