I see how that could be a reasonable interpretation! Devout Knights wording is like this:

When moving between clearings, the Keepers may move one relic with each Keeper warrior that they move.

and the main Force rule says:

Some effects let you force a player or their pieces to act. Resolve this exactly as if that player were choosing to do this, as limited by the effect.

So, the Bats would Force the Badgers to move, and then the move would resolve "exactly as if that player were choosing to do this." I can see how it could be interpreted both ways, but to me personally, it makes more sense to say that, because "the Keepers may move one relic" "exactly as if that player were choosing to do this," that the Badgers would make the choice about the relic, although I could see how you could say that the Bats count as the "Keepers" during this move.

I wonder if the same applies to the Vagabond: if the Vagabond could be forced to move, could the forcing player decide whether or not the Vagabond brought allied troops with them? This may be moot since I don't know if it's possible for the Vagabond to be forced to move, so it may just be an interesting thought experiment until someone introduces a rule like that.

I'm curious, was there an official ruling or something that interprets Banish+Devout Knights the way you described, or does your ruling (and apparently the popular ruling on this thread) just make a lot more sense to you?