We always bred the Arabs at two as well, not just Minis and, for the record I always bred my Arab mares at two as well- obviously had there been a reason not to then it would not have happened but since these were animals I had bred and raised myself, I did it.
Reasoning thus- mostly these were animals that would go on under saddle.
Back at two whilst in foal or getting in foal, ride very, VERY gently as a tow year old until pregnancy precludes riding- usually by five- six months (I would ride an older mare longer, this is a baby remember)
Once she has foaled down and weaned the foal she will be three and a half- back and ride again and probably either bring out under saddle as a four year old or sell on as a "made" animal, who is "complete"- ie backed, ridden and had a foal.
This mare can now compete until she is ready to stop, she has had a foal.
Whereas it might be dangerous to put an older mare in foal, or difficult, a mare that has bred a foal can come back to it happily.
So that mare might go on under saddle into her teens and then become a broodmare in safety (as far as it ever can be)
Would I do it now??
I honestly do not know, probably I would do it exactly the same but start a year later- I find as I get older I become more patient, perhaps??
I don't know, it depends entirely on the mare.
Colts are different.
If I have a smashing colt who has done well in the ring I want to put him on a few mares and see if he is as good as he says he is- if he is not he would be gelded, obviously.
So I will happily put a two year old on up to five mares- if I have a broad enough spectrum of types and heights to allow this.
At the moment I do so my two year old has gone on a tiny mare, a taller mare and a mare that always throws excellent foals (No proof there as the mare throws good foals, I just want a foal from him out of this mare!!)
If I had had more mares empty I'd have put him on two more but all the others were set by the time I bought him.
This of course is all natural cover, managed by myself- I have never had the need to get anyone else involved!!
As far as I know my breeding management is pretty much standard, so you can add "internationally" to Nationally!!
Nathan, as saids, you are entitled to your opinion, so long as you accept that that is all it is, one opinion, among many, each of which is as relevant and often far more experienced than your own.