There's literally a wiki page on this:
https://en.wikipedia.org/wiki/Alcohol_in_Russia.
TLDR; The Russian government hasn't always been pro-alcohol. Alcoholism has been a problem in Russian culture for a
long time, and several governments (including the Bolsheviks ... at least initially) took steps to combat it.
But also ... both Ivan the Terrible and Stalin (as well as less famous Russian governments) created government monopolies on alcohol, and then made huge amounts of money off them (we're talking like 1/3 of the country's entire budget!)
When your entire base of power depends on the money coming from alcohol, you're pro-alcoholism ... even if you're not really pro-alcoholism.