They already have a confirmation box when you try to change the extension. And could just as easily move it into another column where it's harder to change (explorer was like this once, a long time ago).

And yet, they keep hiding the on the rationale that it confuses the users. The most common thing on explorer is some user being confused because they can't understand what clicking on a file is supposed to do, but that's not an argument for showing them...

So, yeah, that's the surface-level explanation. But there's a deeper reason.