I have property in a pretty rural area (Anza, CA) and every goat owner I know says that they're actually picky eaters. But these articles I see pop up now and then pretty much prove the opposite...
There's truth that goats will put most things in their mouths. Almost every time I bring something new into their pen, they check to see if it's food. They'll even check me every now and then just to be sure I haven't become food in the past week. So, sure, you might see a goat pick up a tin can for a brief moment, but you'll also see it spit it out 5 seconds later.
I agree goats are picky the point that if you keep an on them you can catch them before they tear up anything you want to keep(apple/peach trees). Another thing is goats are just dang fun. Pigs and cows are friendly in a dull sort of way, goats have character & personality. One of my goats will come out of his pen nightly just to hang around with me and the kids. When it gets tired of us he puts him self back in the pen.
If you're using goats to clear land, you put more goats per space than the land can sustain, but just for a few days or weeks. The goats will eat their favorite things first, but then also other paletteable stuff. They'll also trample things down pretty good.
Not animals you want around flora you care about.
Yes. Many grazing animals are like this. It's like they have no "feeling full" in their tiny brains. Grass and leafs are not very calorie dense so they kind of have to.
Cows or horses can easily eat themselves sick if they are let into high grown grass fields. Where I live the horse owners will sometimes cut the grass in the fields before they let the horses go to it in the spring.