Let me put it like this: if some alt-right joker played Pokemon Go at the Auschwitz site just to get a rise out of people, how would you feel about Polish authorities jailing him?
If some alt-right joker did that, I’d expect him to be evicted from the site, and have no other sanction applied. If he resisted being eviction, I could understand him being forcibly removed, even arrested for creating a disturbance or some other misdemeanor if his resistance was serious enough. In terms of legal sanction, I’d expect at worst that he’d be assessed a fine. Anything more severe strikes me as clearly excessive. And even those sanctions are only appropriate because free speech is not a license to disrupt, and I’m assuming that the hypothetical alt-right joker was being actively disruptive. If he’s minding his own business, then even eviction sounds excessive.
When the American Nazi Party marched through Skokie, they were entirely within their rights. Those Westboro Baptist jerks who brandish signs saying “God Hates Fags?” That’s protected speech, provided they are not directly harassing individual people. Ditto for anti-abortion protestors waving graphic images of dismembered fetuses; if they don’t disrupt access or harass individual people, they are wholly within their rights. Ditto for cartoons depicting the founding prophet of Islam as a pedophile, or Ronald Reagan as a zombie cannibal, or Hillary Clinton being raped.
Of course, Russia is not obliged to be absolutist about free speech; few countries are. But that’s the way free speech works: the test cases are jokers, clowns and jerks, and if you don’t pass the test when your personal god is being blasphemed against, then you don’t really believe in free speech.