They decriminalized it during Lenin in Russia and Ukrain only but acceptance didn't really arrive, attitudes were mixed at best. At around 1925, if I remember correctly, it was labelled a mental disorder and after Stalin took power it was criminalised again with a minimum of 5 years of forced labour sentence. Any organising by gay people was labeled a fascist or anti revolutionary movement and punishments for that were much harsher.

So for a brief period of about 8 years attitudes were better than a lot of the world but it was by no means a good place to be gay. And for the rest of the USSR existence it was a lot worse.