Maybe he was out riding the thing not polishing. Ducati riders seem to be made up of polishers and riders, riders don't deride the polishers so don't slate the previous owner, it was his bike before yours and sounds like he rode the thing instead of stripping and cleaning, remember what Ducati's are for. Says me who has his in pieces (repairing not cleaning though). I wash mine when I can't see the headlights because of flies.
The guy had bought the bike from new, put 8000 Miles on it and not once cleaned it. Dread to think what his knob smells like. Poor girl. Scumbag.
Gunk can be quite agressive i've found but it certainly does the job. Smells nice as well. Things like muck off have been known to damage anodising if left on too long.
Parafine is probably the safest thing to use followed by a tiny bit of muck off to de-grease it.