How does someone who is not interested in computing supposed to know this?

I found it by accident. Either by noticing the icon changing as I hit modifiers, or by coming across it in a thread just like this one.

As noted above, discoverability of this function sucks, so “accidentally“ is about the only real way to find it.

That interface isn't designed for them. Not everything has to be for everyone.

The attitude that an interface has to work for novices as well as experts is one of the reasons that interfaces keep getting worse.

Or by dragging with the right mouse button.