Maguire's not a bad commentator IMO but, like some (note emphasis) academics, he doesn't seem to have a great deal of real-world experience to fall back on. Moreover, he's not and doesn't claim to be a lawyer. What he is, however, is a reasonably skilled self-publicist, able to have his views generally accorded a much greater level of respect than they in fact merit.
He does, to be fair, seem to me to try to be balanced. On the podcast where the widely quoted comments came from about hefty sanctions should the PL prove conduct amounting to fraud, he also stressed that the PL would likely find it hard to prove the case against City. However, while both propositions are true, there's only one part of that been reported and no prizes for guessing which. In the current, clickbait era, it's sensationalism that rules.