Russian and Chinese famines weren't intentional though. In China, because they were literally coming out from being the hungriest country in the planet, and decided to change too much too fast, you can't really turn such a huge country around overnight. In Russia because they needed to collectivize really quickly in preparation for WW2, and the landlords at the time decided to literally burn grain and kill cattle instead of handing their big estates. The numbers offered by western authorities on both are greatly exaggerated without adequate proof.
After the tragic events, both countries saw unprecedented improvements in quality of life, nutrition and life expectancy. These events didn't really repeat after they stabilized, something that can't be said of most capitalist countries to this day.
In capitalism the owner class needs people to be in despair for them to be willing to work such shitty, desperate jobs. Millions of poor and starving people have to exist either in your own country, or elsewhere in a neocolony for one billionaire to be able to steal so much accumulated capital to himself. It's common to see them taking decisions that help with their accumulation at the expense of everyone else (eg. Oil companies covering up climate change). We are already making more food than we would need to be able to feed everyone fairly, yet capitalist countries don't.
Tankies have a lot of confirmation bias. Facts alternate to their beliefs that communism is the be-all, end-all of human suffering don't go over well with them.
It might be if it were actually achievable in the way it was envisioned, but ideal communism isn't the communism we see anywhere in reality.
Why do you believe Communism isn't achievable as envisioned? Is it possible that you don't actually know what is envisioned in Communism, just a few slogans and buzzwords?
There's never be a full communist or capitalist society. What wears arguing over how far towards either we should go. Also, FYI for those that don't know The USSR and China are not communist. Both are/were dictatorships that call themselves communist.
Look up dialectical Materialism. China is 'communist' as they are progressing along the roadmap Dialectical Materialism provides towards achieving communism.
Are they making actual progress on that path, though? They have tons of billionaires, lots of people go bankrupt there from medical bills or are homeless (unlike some other communist countries). The state owns a lot of businesses, but then so does Norway. All their initiatives seem to be related to hurting gay people or making it harder for kids to play video games. They've arrested some rich people and cracked down on some corruption, but that also sounds like it could come from a capitalist country. I can't really find any sort of long-term plan.
The problem is that you won't ever get a full communist country, at least not for a very, VERY long time, because you always get those few fartweasels who end up hijacking it and turning it into a dictatorship. You need to eliminate that problem first, and with how the world is sliding into fascism, it doesn't look like we're any where near close to solving that dilemma
Even when they don't turn it into a dictatorship, they may just turn it back into capitalism, like Russia did. And when that happens, they just sell all the old estates to the highest bidder, making them richer and turning them into oligarchs. And that becomes functionally equivalent to a dictatorship of the bourgeois.