Assuming they really did have a satellite with an FTL drive, how could Gus possibly know where to find Krypton's ruins? In the first film, Superman tells Lois Krypton's location during their interview. It's how Lex Luthor was able to find kryptonite on Earth.
How much worse could it get for the average guy during the oil crisis if people were already duking it out at the pump?
What if there was a real emergency and Superman was still Not Himself? He could sit it out or use the occasion to wreak havoc or even do real damage, possibly endangering people's lives further or even killing people. Zod and company proved a super powered being (three in that case) could terrorize Earth. Their exploits, as well as the junkyard fight, were a sample of what a Kryptonian could do out of anger, spite, or revenge. Also, Superman was censured by the UN, so him retaliating somehow was possible.
