AT&T reversed their policy without Net Neutrality rules in place
After official complaints lodged with the FCC. Also, this was during the time period of the 2010 open internet order[0] and the 2014 court case[1], where ISPs and the FCC thought that the FCC had the authority to enforce "no blocking" violations.
So, saying "without Net Neutrality rules in place" is incorrect.
[0] - https://en.wikipedia.org/wiki/FCC_Open_Internet_Order_2010
[1] - https://en.wikipedia.org/wiki/Verizon_Communications_Inc._v....