Not just Russian speakers put spaces around the emdash, but also the AP style guide.
Also, for what it's worth, UK style guides recommend endash + spaces (but many write emdash + spaces instead), and so do some other languages (eg. German). There are more countries than just America and Russia!
>>n2d4+(OP)
No, I mean in few Slavic languages emdash is replaces "is a / ist / est / es / ...", therefore you will see it in 99% of ru/be/uk Wikipedia articles *in the first sentence*. Coincidentally, in these languages emdash must be surrounded by spaces (no exceptions).