It also uses them correctly—with no spaces. I have never seen anyone do that on the web.
Almost everyone I’ve seen using them on the web (myself included) does that. Very few people I’ve seen set them open.
(Lots of people use en-dashes set open instead of em-dashes set closed for the uses for which they are interchangeable as a matter of stylistic preference, though.)
I believe this is specific to the US. Writing from other English-speaking countries often uses an en dash surrounded by spaces instead of an em dash.
I didn't know that was the correct way to use them. It feels incorrect in a space delimited language. Interesting.
English is not actually a space-delimited language; that's an approximation which is, in this case, throwing you off.
Punctuation is usually set closed on at least one, if not both, sides, though there are exceptions.