That's actually a super weird implementation. I can hover over a link and open a modal preview, and then hover over a link in that modal to open another modal, ad infinitum. I ended up with 20 modals covering the page, and then moved my mouse a little too much and they all disappeared at once.

Also, if you click on something in the modal, you end up getting redirected to a new page anyways, which kind of supports the anti-modal argument.

OTOH, I like Wikipedia's hover previews just fine, so sometimes they're OK.