How to Handle Agressive/Abusive Handlers?

I thought horses didn't understand boundaries like that. If he can move at all while tied up, what makes clipping any different?

It is very easy to tell how young you are and how inexperienced you are with life. You are just not willing to let this go, you want to prove to everyone around you that instead of listening to adults with alot more experience with horses and life in general, you want to have the last word and keep this going.
I can teach a dog to stand still like a statue in the show ring, but when its outside waiting to go in, if it moves its feet, that's okay. The dog knows the difference when he can move and when he can't. A horse would be the same. They do have understanding of training.
It is her horse and her rules, not yours. If she insists on the horse standing still for grooming but doesn't mind him moving around for being tacked up, then who are you to decide what is right?

Whether the horse's owner's methods are right or wrong are a moot point.

What is the point is that this is none of the OP's business. Whether you or I agree with the method of handling or not

On my drive to the farm where our horses are kept, I pass many many horse farms.....and I disagree with how alot of these horses are kept....i.e. Paddocks a mud pit, junked cars in field, no daytime hay supplementation now that grass is dormant in my area, none with blankets, some with no run in sheds, overcrowding of 11 horses in a small paddock, etc....the list can go on forever.....So, I could come up with a list of things a mile long that I disagree with, but really...who cares? If I stop and make suggestions to the owners about what I think they should or should not do, I am going to make alot of enemies and nothing will get changed anyhow...and I could even get shot!

Bottom line, NO ONE is going to change their methods because YOU don't like it. You can buck and rear about it now, but in the end you will see.....the world does not need to follow your rules, and it wont. Maturity is achieved when you can come to accept that.

Or...just maybe she had not told her horse to stand still at that time.

You horse is not trotting every minute you are sitting on it, but it is still wrong for not trotting when you tell it to trot.

Moving while being clipped can be dangerous. If a horse moves into the blades of the clipper, they can be cut. Especially if they are being clipped on their head or ears. A horse drops their head at the wrong time and - no forelock. They aren't going to be hurt if they move into a brush.

When I see people doing some thing bad I ask them to stop so I could get to a save place before they get kill-that some time opens up away of taking to them about there behavior other time they say what is it to me and I say I do not wont to be here when they come to take your body away that is way to much paper work for me