Let's think about WHY the term is so perjorative. I believe it is because society was so down on illegitamate children in times past (because someone would have to pick up the tab, possibly for religious reasons) that many of them became bad actors in reaction to their constant ill treatment--real bastards, so to speak. Of course, there's also the family pathology aspect of single parent upbringing, which may or may not be more relevant to our times than times past.
The Noblemen of France and England were apt to be quite democratic about sowing their "seed", and there were often revolutions based on dissatisfied barons pledging loyalty to one royal bastard or another.
Incidentally, one of my children ( I forget which one ) was legally a "bastard" until adoption. Perhaps this explains why I am a bit sensitive about the term...