I assume that based on this group's standards, it should include coming to Pinkie's defense in this episode too. So, how should this work?

I don't know if you can actually defend Pinkie on that particular instance, there's no excuse for her behaving like that. She has always been overprotective of Fluttershy and aware of how sensitive she is. She would not try to amp up Fluttershy's fears, especially not after being told off for it the first time around. That's not to even mention how much she was clearly upsetting Fluttershy.

But to be fair, all it would've taken to clear up the trouble of the potrayal, would've been to include this exchange from "Maud Pie" after everything was said and done:

5921866 Sorry to disappoint you, but if this group can't defend Pinkie on at least one point from "Filli Vanilli", then this group is making the same exceptions that Twilight Sparkle was making to stop Starlight Glimmer and Trixie from becoming friends. Protect Pinkie is the name of the group, so by its standards, this group should have thought of this episode before it was even formed.