It was a translation error. Red abilities can be used once per threat phase.
Yes, I see the ambiguity is in the original French rules:
"Les capacités écrites en rouge ne peuvent être sélectionnées qu’une
seule fois. Il n’y a aucune limitation pour celles écrites en noir."
"The abilities written in red can only be selected one time. There is no limitation for those written in black."
So the source of the ambiguity is the meaning of "une seule fois".
The intention, as CROC has clarified, is to make it clear that no additional benefit can be gained from selecting a red power more than once in a single phase. For most of the red abilities this is already obvious, but importantly you can't place more than one die on "The Calm Before The Storm" to gain more than one Destiny Die on your following turn, nor can you put two odd-even pairs of dice on "They Are Legion" in order to gain a +2 DEF.
However, it does appear that you can place four odd-numbered dice on "Supernatural Speed" and gain a +2 MVT for that phase. CROC, is that correct?
EDIT: I see that this question has already been answered here. (Yes, you can select Supernatural Speed twice for a total bonus of +2 MVT.)