You make it seem like Tony is an idiot when in fact it is Steve that is more of an idiot by modern standards. Steve is a man from the 1940s stuck in different time. Tony has given the middle finger to the government many times over and he knows signing the accords isn't meaning they cannot bend the law ever but in effect avoiding a war with 117 countries. In case it isn't clear, by not signing, you are in effect the enemy of 117 countries (USA, RUSSIA, NIGERIA, WAKANDA, UK, GERMANY....add every other country to fill)
I'm not saying Tony is an idiot, I think he overreacted, like everything;
- he sees his weapons in the hands of terrorists, stops weapon manufacturing
- he sees the team getting killed by a second wave of Chitauri, he wants to build a suit of armor around the world, creates the Ultron-program and injects an alien AI to power it
He does so with the best intentions, but he's a tinkerer, build first, fix faults and errors later.
There could be a form of government oversight where there's accountability after the fact. The Avengers operate as they always have, and account for their actions afterwards to the nations in question. They can still operate wherever and however they want, however, they need to consider the consequences. That's a form of accords Steve would've signed in a heartbeat.
The accords in their current form make the Avengers a special forces strike team to NATO, which is far from ideal in Steve's eyes, and he's right. We've seen various situations in the real world where the UN should intervene but couldn't because the government of the nation involved refused help and situations where NATO has intervened but due to ridiculous bureaucracy and / or rules of engagement ended up as a paper tiger in a warzone (Srebenica for example).
I get why Tony would want to sign these accords in their current form because he thinks it's better than no oversight at all, and there's something to be said for that, because after all, it's understandable the world's governments get a little shaky when there's a private military force operating without any kind of accountability of oversight, while there are people dying under their watch. And I get that he's ready to sign these and work out the details later, because that's how Tony operates, get things done quickly, fill out the details later, his various suits are a perfect example of that, most significantly the Mark 2; get the fundamentals in order, work out the kinks as they come along.
On the other hand, I also understand Steve's position. Steve has a strong sense of right and wrong, as do all Avengers, and he feels he doesn't need a governing body to tell him when and how to act. Nor does he need someone to tell him he messed up, he knows when he messed up and he deals with that every single time. "In this job, you try to save as many people as you can. Sometimes, that doesn't mean everyone." is a strong line that captures his way of thinking, Cap is a soldier, someone who recognizes that when you go to war, people will die. And he will try his very best to minimize casualties, especially civilian, but sometimes there's no way around that. And remember the very first mission Cap took was a rogue mission, against orders, to go behind enemy lines and retrieve Bucky and the other POWs held by HYDRA. After the mission, he was ready to face whatever consequences there were, because he knew he did the right thing. His CO just didn't know yet that rescueing those POWs was the right thing to do.
Being the enemy to 117 countries wouldn't exactly be novel either, technically speaking, before the Accords, they were already enemies of said countries. They entered Sokovia without permission I assume and while I'm not sure about Sokovia's membership to the UN or NATO, being a foreign combatant in a country is an act of war. If Sokovia is indeed a UN or NATO member, it's automatically an act of war against the entire UN or NATO, making each member of the Avengers a wanted man/woman/android. Yet, each of these countries would be grateful if the Avengers would swoop in and save them from a second Chitauri invasion. So I wouldn't worry too much about that "enemy of 117 nations" thingy if I were Cap.
