It's hard to understand any of the uses for these techiniques unless you work in an environment where they may be needed. Where I work we are taught how to retrain teenagers when they are a danger to themselves or others.
We use restraint only as a last resort and not one of us enjoy doing it. Sometimes we have to do this as a child is trying to harm themselves. We use techniques that do not rely on 'pain compliance'.
Other times, a child is deliberately trying to harm staff. Some of the children (Yes, even those as young as 12) are bigger and stronger than me. I have never yet used pain complaince techiniques as there has always been another way. However, if I were put in a position where I felt my life (or that of my colleagues) were in immediate danger, I would not hesitate to use pain compliance techiniques to stop that situation.
If someone were holding me by the neck (from behind) and were restricting my breathing I would rather 'scrape my foot down their shins' or elbow them in the ribs then risk being killed. This does happen. Sometimes children will attempt to injure or even kill staff. In these situations were shold respond with the 'minimum force' needed. Usually, the minimum force needed is non pain compliant restraint. Sometimes more force is needed.
These techiniques are an absolute last resort. The article doesn't give the full picture. It doesn't talk about all the non-pain relaint techiniques that are used, and it doens't appear to note that these techiniques are (or should be!) reserved only for situations when life is immediately at risk.
There will always be some that abuse their power, but these techniques, when used properly, have a place.