No, the hallmark of an assault is lack of consent. Since the words "they let you" modified the word "grab" it was the hallmark of consensual sexual favors by a groupie to a celebrity. Trump was a playboy and a Democrat at the time. With the same kind of faults of many other playboy Democrats.
Common decency and honesty precludes accusing a playboy Democrat of "assault" for consensual contact. Even if the Democrat playboy becomes a Republican Presidential candidate years later.
Is it rape culture when people say they have someone “by the balls”, meaning they have the upper hand? Same difference.