We're perfectly allowed to kick people who are being particularly stupid with the gear they wear into a dungeon. If they are:

1. Wearing gear that totals to an average item level lower than the requirement.
2. Wearing any gear, especially body pieces, that do not contain the job's main stat.
2a. Wearing any body pieces that do not contain Vitality.
3. Spiritbinding a weapon.
4. Spiritbinding equipment that cannot be converted to materia(ie. Legionary Visor, most Green Dungeon drops, etc.)

That person is likely to be a troll and should be kicked.