I usually ask them to aoe if I see that I pulled 8 mobs and they're sitting there using single target abilities. Most comply, some don't, I kick the latter. It's pretty simple. It's not an "opinion" that aoe is more effective and efficient, and if you're using single target abilities when I've pulled more than 4 mobs, you're either new (at level 70? really?), lazy, or you don't respect other people's time. If your "personal playstyle" is to single target burn big trash mobs, maybe XIV isn't the game for you.