This is how rooster pecking orders are in the animal world. I have over 35 years experience with farm birds. They stop threatening and attacking humans and never ever have problems with them after a week or two. I do not harm them. It is asserting your dominance over them and showing were they are in the pecking order. They never ever attack us, our children, or grandchildren. None were ever harmed and never had any issues with elevated heart rates. Guess you would rather just end up culling them than try to actually correct bad behavior. That’s your choice. But I also know from experience what happens when a out of control rooster can do to you if it punctures a major blood vessel on an arm. I have a scar and was in the hospital as a child from one that causes me to this day to have a damaged main vessel. Would you want to risk that with your children. And what makes you think that flapping your arms at them doesn’t raise their blood pressure anyways. And it is more threatening to them than being dominant over them, they most of the time threaten and attack humans because whether you realize it or not you have scared or threatened them.