Been running Ridorana Lighthouse the whole week and...

[Awha]

You keep saying that but you don't.
My personal reasoning for wanting role priority is so I can help my raid team. If my gear gets better then the team has increased chance of killing the boss. Sure something might be a minor upgrade for me, but if several individuals get minor upgrades then the team as a whole gets a big upgrade. This reasoning is actually standard across most raiding teams.

You don't get where I'm coming from because you don't look at the bigger picture. You keep going on about how the upgrade won't affect the alliance raid's performance, but you don't even think about how that upgrade might affect other content.

Because those that are affected in the moment will be the alliance raid, who is the say that your current group that you were granted priority over will run more content with you in the future to reap the benefits of your upgrade thus making their future runs better overall. If we are talking a static situation or a PF that does multiple runs I can see where you are coming from, but from my experience most 24's are one offs.

You have no way of knowing what they're going to use it for. You do know, however, that they have the job unlocked at the right level for it. Which is more than enough reason to go "hm. That person probably needs it more than that other person who isn't currently on that job".
Right now, people still roll on the gear with those exact reasons, difference is they win them over people who need them for their main raison d'etre - being used by battle classes.

That is the point I was trying to make the group has no way of knowing what a player is going to do with the gear, and because they do not know why should they be granted priority simply due to their role / job? In a static setting it makes sense, but in a PuG setting granting priority to another due to their role or job seems odd to me. More or less blind faith that they will put the item to good use since they have happened to queue with that job in the moment.