I come to you all with a question: why do melee DPS refuse to do LB3 lately?

I've never had an issue with DPS and LB. You ask and they do it. Now it's like twisting an arm. I've had melee DPS out and out refuse to use LB3 in, say, Susa Ex. Literally saying no in the party chat when you ask them. You think I kid? I do not.

I'm trying to understand what the issue here is. It's multiple people, in multiple runs, and I don't have any melee DPS to 70. I've a SMN and the rest are healers. No one ever asks a SMN to LB3 and I can count on one hand the times I've used LB2 so I thought perhaps there is an issue with casting LB3 that I don't know of?

Does it hurt your DPS to cast LB3? Does it give you a debuff or something? Is it a huge burden to ask someone to use it? What's going on here? Why are people refusing to use it?