What do you mean by "safe"? It's a search engine, it just returns you search results. If you are worried about JS/tracking... well, Google and others are already tracking you. I use Apple devices, so Apple knows everything about me as well. If you are worried about the links you may click when yandex returns you search results, there is nothing special about yandex, same rules apply as in the wild wild web: double check what you download (e.g., do not double click "rihanna-song1.mp3.exe" on Windows!)
He may mean "is it infested with malware"? Historically there were a lot of warez or porn sites based in Russia and East European countries which were.
I also "heard" about them. But all warez sites that i visited were good quality.
May be propaganda from BSA.
Much of the Russian bot farms turned out to be imaginary anyway (docs released by Twitter recently) so I’m not worried.
Even if Putin himself could read your searches, would you care? I guess don't use Yandex if you're a Ukrainian soldier but otherwise what are you worried about?
Yes, there’s no telling how states like Russia secure that information, disseminate it to other paying customers, leak info about high value citizens to use as kompromat etc.
That’s a double standard because you could swap yandex and Russia with google and US and also have a very plausible scenario of what’s happening right now.