Here are some thoughts on visiting a Portuguese palace.
First, its owners were busy military and royal administration men; perhaps this explains why the interior decoration and the garden statuary is so damn ugly. Perhaps they were too busy to appreciate art, and therefore did not know anything about it. Perhaps stucco was just stucco to them; and statues -- statues. ("Hey, it's Jupiter, alright? Or is that not good enough for ya?")
(Or, since the palace was redecorated following the 1755 earthquake, perhaps they didn't have the money to spend on the best artists available; or perhaps the best artists have died in the earthquake and were simply not available).
Second, generally speaking, the quality of statuary in Portugal is pretty lousy. (As it is, for the most part, in Venice -- just google the Lombardos). Perhaps Don Joao V imported Italian artists not to monkey Rome, or to please the Pope, but because he could see the problem. The truth is that there is no ugly statuary in Rome. (And hardly any in Florence).
Third, an EP observation: anyone used to looking at naturalistic statuary can tell at an instant whether a particular statue represents accurately an ugly person (like Michelangelo's famous Medici bust, above); or whether the ugliness is an ungainly representation of a possible person (such as Michelangelo's Night in the Medici chapel). It is almost as if our brains carried in them some algorythm to know whether a particular deformity is possible -- "natural" -- or not (whether joints of particular shape or limbs of particular proportions will "work"). We almost certainly use this mechanism to recognise charicatures -- what we see does not "check out".
And neither do bad statues.
Most of the statues in the park did not check out. But there was a statue of a lady in the buff; her bum looked bad, but one knew instantly that it was a natural bad bum: such person could indeed have existed and the artist merely manage to capture it in all its glory. (Bad bums canbe glorious).