So my good-hearted mage went into a dungeon with J'zargo. The cave was full of mages and necromancers and, to my surprise, 3 Blooded Vampires in separate cages. I noticed some dead Vampires too so it looks like they have been doing experiments on them. So my question is this:

Should I free the Blooded Vampires, free them and then kill them so they don't hurt other people or let them be locked in the cages?

I'm having a hard time deciding on what to do about this.

Light 'em on fire. Int the cages.

My characters are admittedly ruthless.

I would free them, if they attack you kill them obviously. If they don't attack and run away, kill them as they flee in one shot (if you can). Let their final moments be of freedom without endangering innocent lives.

Morally, I feel I have the right to kill anyone who attacks me. I'd let out the vampires and if they didn't attack me then I'd let them be. It's likely they'd attack you, however.

They didn't attack me. They did call me meat however so ot's reasonable to assume that they're gonna feed of humans in the near future.

I don't think of vampires as being inherently evil. The player can be a vampire, which means a vampire can choose how they behave. Some vampires may live helpful, concealed lives (Janus Hasildor in Oblivion) while others may be violent and destructive. Same with mages and necromancers too for that matter. So the only way I can tell is by who attacks me unprovoked. You may have intimidated them, so maybe they thought it would be prudent to try and intimidate you back? To me it's the actions that matter, not the talk.

Well, I killed the 3 vampires in the cages. They called me meat so I felt they were going to feed of innocent lives at some point. I let them out of the cages and attacked, none of them attacked back but still. I felt I couldn't take the risk, especially when they continued to say "Out of my way, meat". There was another vampire who was in a cage, which was hanging from the ceiling, and there was no way to open it so I killed of that vampire too. I don't wish that destiny upon anyone.

I had a more diffcult time decideing the fate of eldergleem Whatever place thingy...

I let the vampires in that dungeon out of their cages with every intention of letting them walk away unscathed, but then they just HAD to turn around and try to tough-talk the chick who had spared them from a slow, agonizing death by starvation. That's right about where I draw the line at mercy. I let them out one at a time, too, so they had ample opportunity to learn from the mistakes of their buddies. But, nooo. "Out of my way, meat." Stab. "Out of my way, meat." Slash. "Out of my way, meat." Hack.

I killed them and my character is a vampire. I'm roleplaying him as an ancient though so he saw them as inferior new bloods of a different breed.

Vampires eventually need to feed, wether or not they succumb to an innocent is their decision, can you handle that?

Free them. They won't hurt you, let them go.
they fight with you, and are friendly after.

Poor vampires locked up like that.

Playing a vampire I can feed on my husband and he doesn't mind. He's all "Anything else you need my love?" You can be a vampire and live a life where there are never any victims. (And personally there's no way I would ever bite anyone but him. Everyone else in Skyrim is filthy. )

This was one situation that I wished there was more depth. Release them and then at some later point in the game (not in the same dungeon) the vampires are met randomly or in some other dungeon and remember that you freed them. Either that or you (as a vampire) could join them (as in a guild).

Free them and then put their captors into black soul gems

I recall the one hanging in the cage from the ceiling where the novice mages were taking target practice on. Vamp or no, I felt bad as I couldn't free her. Especially after she greeted me with something like "how's it going, handsome?"

Just don't overdue it or you won't have a husband to fulfill your "other" needs

Tough question indeed. Not sure what I'd do myself. Probably let them rot in there (in fear of them rampaging my precious Skyrim). But a good hearted man like you would probab?y let them go