I am quite certain that there are proportionally more communists in post-socialist countries than in Western countries. According to the results of the "Rendszerváltás 30" public opinion survey conducted in 2020 by Policy Solutions, Závecz Research, and the Friedrich-Ebert-Stiftung, 52% of the Hungarian population believes that the relative standard of living was better during the Kádár era, while 31% think it was worse. (Page 24) Of course, this doesn't mean that 52% of the respondents are communists, but the results significantly contradict this meme. Is there any source to support the claim that there is a higher proportion of communists in Western countries compared to post-socialist countries?
I cannot speak for other countries, but here, the Kádár-era remains popular for many people even to this day, particularly among those who lived during that time.