If you RTFA you'd see the claim is that Facebook is activating the microphone to listen to non-electronic verbal communication you're having nearby your phone.
You're missing the point. It doesn't matter at all if there's any evidence that a given claim about a particular version of an app is being tapped; you have to assume that they all are, all the time, and act accordingly. You're never going to know, and certainly not ahead of time; best to assume they're all tapped. Which, as we all know post-Snowden, is the only reasonable assumption.
Most people are aware at this point that non-end-to-end encrypted electronic conversation is being tapped. It seems like a new development to extend that assumption to non-electronic verbal communication you're having with another person physically in the same room as you. Again, communication not occurring via any electronic means whatsoever. Just so happens your phone was in your pocket while you were non-electronically verbally communicating with someone physically sitting in front of you.