What are everyone’s thoughts on the wide zig zag skiers?

I’ve skied my whole life and since I can remember, this one type of skier has always confused me. (It also applies to snowboarders but for whatever reason, it seems to be less common from that group).

The people that ski in very wide S curves. They take up nearly the entire run and they swerve back and forth, but not even in a way that’s predictable. It’s like they just lurch in the opposite direction at any moment.

It was less of a problem for me once I got off the green runs, because it’s much less common in intermediate skiers. But I’m teaching my kids to ski and we are pretty much 100% on green runs now.

Obviously I’ve told them the general rule is that if someone is below you, it’s your responsibility to not run into them. But these people are downright unsafe. They go do slow that you are at risk of someone running into you from behind. You can’t pass them safely. I feel like wide zig zagging should be explicitly taught as unsafe.

Am I alone in this?