Yes, I get that inducing stress to see how people react is needed. What isn't needed is being a dick about it all the time. When the example that you set from the get-go is that the primary method used to "lead" people is by yelling and otherwise forming an toxic workplace environment, you're teaching them from the start that that's how they should be leading people too. And then they go forth, and spend their career making people around them miserable, because that's what you taught them to do.
Yelling has its place, but should be used very very sparingly.
Honestly, I still don't know why you're under the impression this is an issue. The dress instructions update doesn't in any way supercede or overwrite existing policy implemented for safety reasons, and instead very clearly and explicitly outlines that safety is a great reason to impose such restrictions, specifically mentioning the respiratory health policy as an example of such.