People need to realize that Sanji's siblings aren't bloodthirsty monsters who are hell bent on causing bodily harm to people.
They lack empathy and emotions, which means they are indifferent towards their actions, whether they be right or wrong.
That right there tells you that Sanji didn't just "Blackout and attack a woman", because that's not even how his own siblings function. Right now, his body is going through changes, which could be cause for the lapse in memory, but attacking the girl on the spot for no reason at all doesn't even fit the narrative of his siblings.
Something happened, and Sanji most likely is responsible for it, and just doesn't remember, but I can guarantee you that he didn't just attack someone for no reason.
I mean, I'll even buy that it turns out she attacked him, and he instinctively defended himself because of the situation with his body, when under normal circumstances he would refrain from defending himself against a woman. But actively attacking her just because? Nah.... That's a big nope from a narrative standpoint.