I don't think it's clear that PFOF is bad for retail investors. Many people argue (see Analysis section of the article you posted, and also Matt Levine's writing about it on Money Stuff) that PFOF is actually a net good for retail investors, getting them both price improvement and lower commissions.

Also:

> In the United States, accepting PFOF is allowed only if no other exchange is quoting a better price on the National Market System. ... Transactions must be executed at the best execution, which could mean the best price available or the speediest execution available.