I suppose it's for convenience when yandex doesn't find what you are looking for. Don't worry, Russia isn't exactly a freedom of speech heaven and if the government had a serious issue with these other search engines they wouldn't be there.
At the same time you don't see google or bing linking to other search engines. So I think linking to the competitors for your users convenience is a pretty neat thing to do, which probably irks countless top managers daily. Don't belittle that little neat touch just because it's a russian website.
I'm not even sure if what I posted makes much sense, I was somehow stuck in the context of using alternative search engines to evade censorship and figured that parent suggests that these links may have something to do with it.
https://en.wikipedia.org/wiki/Federal_Service_for_Supervisio...