If you own the means of production, is it really “stealing” though? /s

That's very much how it was justified. There was a saying in USSR:

"Tащи с работы каждый гвоздь - ты здесь хозяин, а не гость."

translating to:

"Grab every nail from work - you're the master here, not a guest."

essentially parroting the Soviet cliches about how proletariat was in charge etc.

Not to totally discount embezzlement, but I think people underestimate just how poor these countries were after world war 2.

Usually people are talking about the 60s-80s when sharing these stories since that’s what grandparent/parent generations remember. USSR did experience significant growth at least at the beginning of this period and most of that theft/embezzlement was certainly committed to later sell/exchange those goods for profit (e.g. working at coffee shops was were lucrative since you could just reuse the same ground coffee for 5+ cups and steal the rest).