This is excellent advice, and I agree.
I learned from an old-time Arabian breeder, and I've treated my minis just like any horse. When with me, we focus on whatever the task is. He has approximately 22 hours a day to do as he pleases, so he can behave while being fed, handled, worked, etc.
We, as well as others I respected, did as Standards Equine suggested: in with geldings while young, or other stallions during winter if they get along. There was something about being in a bachelor herd that allowed them to well and truly relax. Some breeding stallions never get along with other males. You need to assess this for yourself.
We, as well as others, often kept the stallions with a small group of cold mares too. Nothing like a swift kick in the chest to get an over-amorous male to understand that "no means NO."
There were some instances, however, where this wasn't possible. So stallions stayed in a stallion barn, and mares in a mare barn.
As the owner, it's your responsibility to be aware of whether or not your horses have enough space to get away from each other if there are disagreements. The only significant injuries I ever saw were between horses where one was cornered.
One last thing, and it's a nifty trick I learned from the above-mentioned Arabian breeder: he wore a frilly, 1950's glamor style apron when it was time to breed!! Even while cleaning genitalia, he was dressed normally. One the stallions saw that apron come out and get tied around the waist...wooooo weeee did things change!! The fire-breathing, snorting, blowing, manes and tails flagging stallions came to life! It was a nifty trick and has served me well over the years.
Edited to add because Taz was posting while I was: what she ^^^^^^ said, too.