Imprinting is great, and it can start by talking to mama horse belly. I prefer foals handled from birth and the desensitizing mixed in with mare/foal bonding can be a boon. I think it's all in how your view and do the desensitization. Of course if you come in dominant and abrasive, disrupting the mare/foal bond, and handling the foal harshly (I don't know if you can call that true imprinting) that could do more harm than good.
I would never say proper imprinting technique is abusive. I think if the horse is born without the company of people, never handled, and then "broke" at a year, that could do much more harm. It's actually the custom that could be harming this breed. Minis should have the reputation of a gentle, noble, and intelligent character, WITH manners. Most of the time this comes from handling at foal-hood and throughout. Teaching them to be halter trained, have their hooves handled, and stand for clipping is all a part of that. Even if the horse is a born stinker, he should still be taught to stand tied and have his hooves handled at the least.