Frankly, this is an absurd line of argument. Communists in Russia tried doing something that’s never ever been done before, and they didn’t get it perfect the first time around. Saying that we shouldn’t keep trying seems a little odd to me.

USSR collapse doesn’t say anything about validity of Marxism. Capitalist states collapse all the time, and states with every type of government known to man have collapsed over time.

What needs to be asked is whether USSR worked for the people who lived there when it was around, and how that compares to the alternatives. USSR did quite well in that regard by ensuring everyone had food, housing, education, healthcare, and work. Plenty of research on USSR shows that it did a good job ensuring that needs of the majority were met. Some details here for those interested.

Today, China is a state governed by the Communist party where Marxism-Leninism is the official state ideology. 87.6% of young Chinese identify with Marxism, and the party has 95 million members. Chinese government practically eliminated poverty, and in fact China is the only place in a world where any meaningful poverty reduction is happening. If we take China out of the equation poverty actually increased in real terms:

If we take just one country, China, out of the global poverty equation, then even under the $1.90 poverty standard we find that the extreme poverty headcount is the exact same as it was in 1981.

The $1.90/day (2011 PPP) line is not an adequate or in any way satisfactory level of consumption; it is explicitly an extreme measure. Some analysts suggest that around $7.40/day is the minimum necessary to achieve good nutrition and normal life expectancy, while others propose we use the US poverty line, which is $15.

China does massive investments in infrastructure. They used more concrete in 3 years than US in all of 20th century and built 27,000km of high speed rail in a decade. 90% of families in the country own their home giving China one of the highest home ownership rates in the world. What’s more is that 80% of these homes are owned outright, without mortgages or any other leans. Real wage (i.e. the wage adjusted for the prices you pay) has gone up 4x in the past 25 years, more than any other country. This is staggering considering it’s the most populous country on the planet. Chinese system also results in high social mobility unlike western capitalist alternatives.

Finally, plenty of people in the west admire Churchill who is responsible for genocide on a scale of the holocaust in India. So, not sure how people admiring Stalin is any different from that. US is also responsible for far greater atrocities than Stalin. The country is literally built on genocide with US settlers doing to the native population of North America precisely what Hitler aimed to do. In fact, nazis were directly inspired by US race laws, but even they found them to be too extreme initially: