The link she is talking about is about delaying the high-risk foods for so long beyond 6 months - not due to solids being started at 6 months. However, the way this has been marketed to many MCHNs by commercial companies is very misleading.

Recent studies have also shown that there is no "one" thing that is a magic cure for preventing allergies. It is quite complicated and there are a number of factors which contribute. If it was as simple as "change this one guideline and the allergy rate would instantly fall" it would be great - but it's just not that simple.