It is the FCC who is responsible to keep the spectrum clean of pollution; not the job of the ARRL.
During the BPL comment phase the FCC had thousands of comments from the amateur community explaining the problems. The FCC has decided to ignore the problems of BPL and the subsequent interference.
BPL is a gross polluter of the worst possible kind. The FCC is responsible and FCC failure to take action is totally irresponsible.