Actually, yes! I was in my own world fuming over the upgrade debacle when the male FA stood over me for a few seconds glaring until I uncrossed them so he could take his seat for take off. He was nice enough after that and never scolded me specifically for leg crossing so in my book it's still fair game.
Did the (male, but why does this matter unless you think it might have been the same FA the OP reported) FA ever tell you to uncross your legs? If not, why do you think he was glaring about the crossed legs?