Based on my limited insight to the rule change, it wasn't the USGA that pushed for the change, it was the R&A, after Els won The Open. According to the articles I've read, anchored putting is not as popular outside the US, and after seeing Ernie win their major the R&A decided that they needed to ban anchoring before it became popular outside the US. R&A told the USGA of their intentions and gave them the option of joining in the decision or to have this affect only play outside the US. USGA felt it would be confusing to have 2 sets of rules and joined with the R&A.
Where on earth did you get this from?
This discussion has been on the Joint Rules Committee's agenda for some years.