He is the classic over-maintainer, utterly clueless, with a cult like following of the equally clueless. The only reason for the existance of phosphate free coolant is that it is more compatible with hard water. It has nothing to do with engine metallurgy. Very hard water + phosphate inhibitor coolant can result in precipitates, hence the clogged cooling passages reports. Of course, even a moron knows to use distilled water in a cooling system, right? Phosphate inhibited coolants provide superior corrosion protection and unmatched water pump erosion protection. Why BMW speced an inferior coolant to guard against idiots using hard tap water is a mystery.
Cutting and pasting completely wrong asserstions and assumptions from your guru makes niether him nor you correct.