The author put "front-running" in scare quotes for a reason. See footnote 6, where he explains he's using the term in the Michael Lewis/IEX sense.
He's technically "not lying," but many people won't notice the footnote nor appreciate the difference. All they will hear is "front-running == should be illegal"
Probably still worth pointing out, since one of the activities is illegal and harmful (uses non-public information) and the other is just reacting quickly to the public market information.
Liberately quoted:
'[...] man, remember when "front-running" meant something? [...] But then came "Flash Boys," [...] And now, basically any time anyone trades on public information before someone else, it's "front-running," [...]'