2008 World Ice Hockey Championship (Canada)

A man, in Russian, the correct way to write it now is "беларус," not "белорус."

Perhaps you introduced this rule into the Russian language, but in Russia, the old rule still applies, which states that a connecting vowel cannot be the letter "a."
Quote from the Encyclopedia "Peoples and Religions of the World":

Belarusians -
...Belarusians, беларусы (self-designation), a people, the main population of Belarus (7,904.6 thousand people). They also live in Russia (1,206.2 thousand people), Lithuania (63.2 thousand people), Latvia (119.7 thousand people)....

I hope I don't need to explain what "self-designation" means? Or maybe some native Englishman will jump in here and demand that we not call representatives of his people Englishmen, but Englishmen? By the way, how are your compatriots called in Albion? Do they demand to be called "Belarusians" there too?