Did you look at the example for that section? I'll quote it for your convenience:
"Later in the game, Biff is talking to someone in a bar who’s been spying on him, and he knows from a previous assessment that the guy has a Bad Temper aspect. He decides to invoke the guy’s aspect with his Intimidation roll to get the guy to lose his cool and slip up. Because that invocation creates a disadvantage for the spy, the GM gives that character a fate point at the end of the scene, to save for a future meeting."
This is an example given in the section on invoking other characters' aspects. Clearly, it's a invoke used as a compel. The very next section, on tagging, says that tagging lets you "invoke it [the taggable aspect] one time, and one time only, for free". Ie, compel allows invoke; invoke allows compel.
Fred's discussion mentioned above was only a clarification, not a new rule (which is, I believe, how he described the post, too).