Even if Fury did show up in Civil War, what could he say that would make a difference?
"Hey Steve, knock it off with this teenage rebellion of yours, and sign the damn accords."
"Actually, Nick, don't you remember when SHIELD was taken over by Hydra? Right under your nose?"
"Oh yeah..."
"Hey Tony, quit it with the brown-nosing, you've got a decent brain on your shoulders, trust yourself to use it and do the right thing."
"Actually, Nick, don't you remember the last time I did that, you ended up having to save all our asses with an old helicarrier?"
"Oh yeah..."
"Hey Wanda, Vision's obviously got the hots for you, how about you give an android a shot, huh?"
"Actually, Nick, remember the last time we let a robotic life form do what he wanted? He turned Sokovia into a meteor."
"Oh yeah..."
"Hey Clint, I set you up in a nice, secret house in the middle of nowhere so that you could live in peace with your family. How about you go home?"
"Actually, Nick, remember how Wanda's brother sacrificed his life to save me? Do I look like the kind of guy who wouldn't repay that debt?"
"Oh yeah..."
"Hey T'Challa, your highness, how about you go back to Wakanda and not meddle in the affairs of the Avengers?"
"Actually, Nick, remember how my dad, the reigning monarch, was blown up in Vienna?"
"Oh yeah..."
"Hey Natasha, you've never been one to take sides and take a stand, why don't you just stay out of this?"
"Actually, Nick, remember how I dumped all of SHIELD's secrets, including my own, onto the Internet? I need friends now for backup."
"Oh yeah..."
"Hey Sam, help me out here, just stay out of this, won't you?"
"Actually, Nick, remember when I said I do everything Steve does, only slower?"
"Oh yeah..."
"Hey Rhodey, how about you and Stark back down, and stop this from getting any worse than it already is?"
"Actually, Nick, remember how I'm an air force officer and so I took an oath to obey my government?"
"Oh yeah..."
"Hey Vision, you love all life, how about you stay out of the fighting?"
"I am staying out of the fighting. Haven't you noticed I don't use force against anyone except as a last resort?"
"Oh yeah..."
"Hey kid, you're what, in high school? How about you go home and do your homework?"
"I finished my homework already."
"Oh yeah..."
"Hey Scott, you've finally shaken your stigma as a con, why would you get back into all this again? Trust me, just go home, it'll be better for you."
"Actually, Nick, Hank told me never to trust SHIELD."
"Who's Hank?"
"Hank Pym? Inventor of the Pym Particles?"
"Oh yeah..."
"Hey Bucky... actually, never mind, there's no way you're staying out of this."