I don't think the bullshit representation of the Philistines by Biblical authors is all that strange. It's almost a universal trait for a culture to paint its enemies in the worst possible light (Romans of the Late Republic/Early Empire are notable exceptions). Which is going to be more acceptable to the proles:
'We have to attack the barbaric, savage Philistines because they want to destroy us'
or
'We have to attack the learned, skillful, cultured Philistines because they have stuff we want'?
Boru
'We have to attack the barbaric, savage Philistines because they want to destroy us'
or
'We have to attack the learned, skillful, cultured Philistines because they have stuff we want'?
Boru
‘I can’t be having with this.’ - Esmeralda Weatherwax