Maggie and Pope have a few things in common: They both want to protect what their people have; they're both willing to do whatever is necessary to make that happen, and they're both bloodthirsty for some vengeance — even if it's not totally clear why they are fighting each other. (We know the Reapers killed everyone in Meridian, but the explanations aren't lining up just yet as to why this pious group of mercenaries would do that beyond just them all being insane, which most of them don't seem to be.) For Maggie, this all means taking some notes from Alpha and the Whisperers.
She wants to make the Reapers hurt. More than that, she wants to wash over them the way they did to Meridian. And she's going to try to do that with some walkers. A lot of 'em.
Taking some tips from Negan about how to be a good Whisperer, she practices wearing a walker face mask and herding as many of the dead as she can into a pen while Gabriel scouts out the Reapers' home base. He returns and reports back to Maggie that “it's still there,” which makes all of this more suspicious. What exactly is she looking for that's apparently in the Reapers' possession? Are the Reapers currently occupying what used to be Meridian? Is that what he meant by “it”? I still think there's something missing from this puzzle and that Maggie — who's now literally becoming an Alpha, one of the worst people they've come across — might have done something to attract Pope's ire.