Mudra why so many ninja don't use them?

[Jeeqbit]

What I do see too much of is Doton on single-target bosses.

That's because it used to be slightly better to use it on a single target (I think by a single DoT tick). It seems that SE fixed that oversight.

i was confused what my tank stance did i kept spamming it off and on like a random cooldown

I've seen tanks do that occasionally. Rare, but amongst my thousands of dungeon runs, I've seen it multiple times.

[Rithy255]

I've seen tanks do that occasionally. Rare, but amongst my thousands of dungeon runs, I've seen it multiple times.

I think this is because tank stances are pretty confusing, most people aren't going to know what enmity means, but yeah I've seen it a couple of times myself... But i've seen things like level 90 Gladitors so I'm used to seeing wild things in ff14.