Exact same thing happened to me flying UK to Spain. Was embarassing a bit, but certainly didn't think it was worth calling the cops over. Just laughed it off and got on with it!
Of course the problem is that we are relying on a news item for all the facts....had we been there, we might have seen it in a different light. For example, the behaviour might have been highly offensive to other passengers (one hopes that able-bodied crew wouldn't be fazed by anything other than pretty extreme behaviour). It's also possible that the 'assault' had genuine safety ramifications...steward carrying a pot of scalding coffee? But in the absence of that kind of thing, one can only be amazed at the notion this young lady might be sent to prison for up to ten years!!
Not everyone will agree, but I think there is a difference between young lady groping able-bodied man and able-bodied man groping (any) female. I wonder how many people, male and female, would agree with that? I don't think that the law makes such a distinction; should it?