"why did they just pass a law that 18 - SIXTY year olds need to report and fight?"
They're a small country fighting a vastly more populous opponent.
Your contention that Russia is fighting NATO is just more Putin fluffer spank bait. Russia's air defense would be nullified in 48 hours or less and every airfield and missile launch site within striking distance of the border would be destroyed.
Putin himself would not survive. His own people haven't taken him out yet, but they have to be thinking about it.