There were no allegations that they provided a worse price than the NBBO (ie. the price you'd get if there wasn't PFOF), just that out of all the firms offering PFOF, robinhood didn't choose the best one for their customers.
“But the SEC’s order finds that two algorithms used by Citadel Securities did not internalize retail orders at the best price observed nor sought to obtain the best price in the marketplace”
When did the goalposts get moved? Your original argument was citadel/robinhood was "front running trades". That's a more serious accusation than robinhood/citadel not getting the best price.
