Well, I can agree that it's ridiculous and that it does say a lot about our culture when it's newsworthy to point out that a man doesn't get handy with a women posing for a photo.
But it's also what's needed.
It's taken for granted that it's ok to touch other people when doing a group photo, so much so that it comes out as an oddity when someone (usually a woman) has something to say about personal space and discomfort in these situations (beyond inappropriate touching).
The norm is that it's ok and it perhaps we should reconsider that but cultural change has to be drive by something. If we don't reward good behaviour, there's no incentive to follow it. We could punish bad behaviour but the "bad" behaviour in this case doesn't yet come out as bad, not to a degree where it has enough of an impact that it can't be shrugged off.
That's why it's important and impactful to see a celebrity, someone people look up to, setting an example. Making headlines for it is a side effect, but it matters.
You and I can agree it's a basic thing but from considering it as such and it becoming a social norm there's a long way and Keanu helps push that along.