"I am stunned how many people on here focused on the fact that she kicked (which is not OK btw!) rather than how he responded to it and actually frightening her."
People are focusing on the fact that she kicked, since that's what started everything off...! Surely?!
OK, picture the scene. You're a parent of a young child or children. Your daily life revolves around them and their needs - it's the way it is, you get on with it. One nice weekend morning you wake up and decide to risk it go out for brunch, taking the DC with you and do something nice, and reminiscent of the days of yore, pre-DC when you could do this sort of thing at the drop of a hat.
You get there, order your food, relax into your cup of coffee when someone else's brat PFB darling little one starts whining. A little later, just as you're tucking into your eggs Benedict, said darling starts "playfully" kicking you under the table.
No. Just no.
Sorry - but if I'm out for one of those rare non-child-focused treats that is dining out, then the thought of some child kicking me "playfully" under the table would drive me to despair. An irrational over-reaction? Almost certainly. But still, it would.
Would I personally say something? I dunno, probably not because I'm a total wuss, but I would be seething with resentment inside at the annoying (read: NOT fun and playful) child.
I certainly wouldn't fault someone else for saying something.
OP - you're perfectly in your rights to be miffed by this, but so is everyone else within the rights to think you're being overly precious. If you don't want others telling off your child, you either need a 100% perfectly behaved child, or you need to watch her like a hawk to ensure you get in their first.