The Siberian battalion consists mostly of people "from ethnic minorities from Russia's far east". Modern Russia is a huge quasi-empire, with Muscovy oppressing all the colonized nations and regions. Ukrainians, being formerly colonized, feel with all the oppressed nations and support their fight for freedom.

That's why Ukrainians actively support the "Free Nations League" https://freenationsleague.org/ and this Siberian battalion. Imperialism is deeply ingrained in the flesh and bones of Muscovy, so Ukrainians are wary of it.

Muscovy destroyed the democracies of the medieval republics: https://en.m.wikipedia.org/wiki/Novgorod_Republic https://en.m.wikipedia.org/wiki/Pskov_Republic

Ukrainians have way more in common with these democracies, which were the closest allies of the ancient Kyiv state, than with Muscovy, which has always sought to oppress and enslave Ukraine.

Whatever Muscovy says, it will inevitably seek to oppress due to the law of "imperial boomerang" https://en.m.wikipedia.org/wiki/Imperial_boomerang

We can be true friends only with free people of independent nations.