There are obvious things like "should we just blow up the planet for lolz?" where you don't need to be an expert. But there's also a lot of stuff where a universe of complexity expands once you look close enough. Things have unintended side effects, and the average voter will not and can not spend the time to look close enough to even notice that there are side effects, much less what they are or how they are connected.

"That's easy, just do X" is usually something non-experts say, me included in things that I know nothing about. I like to look into some of those things and usually learn that it's not as simple as a cursory glance makes it look. That's also why most people shouldn't be day traders.