I don't know why people trust companies more than governments. Both can be large and powerful. Also I find it highly unlikely that these certificates get abuse

I don't know why people trust companies more than governments. Both can be large and powerful. Also I find it highly unlikely that these certificates get abused: - Those certificates are from other branches of the government. They won't like the NSA abusing their certificates. - When abuse of these signatures gets detected it would be a big scandal. It's way more easy and stealthier to steal the keys of a intermediate CA.