How do you persuade them that you're right or how do you come up with an argument that makes you feel like your chosen ideology does not have any flaws?

The first: you probably can't. They are just as set in their world view like anyone else arguing on the Internet, including you and me.

Second: accept that all ideologies have flaws. Policies however well meaning have to survive contact with reality first and foremost. Or in this case reality has to survive contact with the policy.

Let's clarify.

https://en.wikipedia.org/wiki/Soviet_famine_of_1930%E2%80%931933

Are you saying that the famine didn't happen, that the same famine would have happened regardless of the economic system, or something else?

I'm not against communism, and capitalists can make similar damaging calls.

https://en.wikipedia.org/wiki/Dust_Bowl https://en.wikipedia.org/wiki/Great_Depression

I think both systems tend to produce oligarchs through different methods. The point isn't to pick a team and rally them on, rather let's look at things honestly and consider information hostile to our viewpoints. I think it might be possible to build something better than both.

I'd say "the fuck do I care what Stalinism did, I'm an anarchist" but if I felt obligated to defend Marxism in general from the actions of its hypocrites?

The British Empire and British East India company for example caused both Bengal famines (and the Irish Famine, and numerous famines in Africa, etc etc etc) The lesson is not truly that either capitalism or communism is to blame, but authoritarianism and statism as a whole.

Famine is used as a weapon by the people that won't ever need to worry about where their next meal comes from. Those people can be capitalist as easily as communist, but it does make the communist a hypocrite. Can you say the say the same about the capitalist?

I mean Mao's stupid bullshit didn't exactly help...

Literally things improved after his death because Deng Xiaoping oversaw the opening up and reforms

I suppose I would start by saying "Communism lead to famine in the USSR and China" is like saying "Capitalism lead to Nazi Germany and Fascist Italy".

It's down to the application of the system. True Communism gives power to the ordinary workers. It is not meant to be concentrated in the hands of an autocrat or an elite. That is precisely what it aims to prevent.

The last two points are just not true. The incentives are, in theory, workers having better standards due to better wealth distribution (if it is managed properly) and they don't use capitalist products because the products were made under a Communist system, so that's just ridiculous.

Communism has many flaws. Personally I think it's more of a pipe dream myself, but the arguments you have stated against it are not good ones.

Do you think people aren't intrinsically motivated to feed themselves? Also, those famines happened because of a guy named Trofim Lysenko got into Stalin's good graces while having some batshit unscientific ideas about botany. You don't need communism for that, see RFK Jr, or the cigarette industry, or everyone who denies or downplays climate change because they don't want to have the deal with it.

I'm not a communist myself, but the last point is so fatuous that I think it's fair to conclude that anyone actually making it is not arguing in good faith.

The first two, though, are completely valid arguments and you should respond to them by ceasing to describe yourself as a communist!

As for "using products of capitalism", ask them why they use a phone made in communist China.

There was only ever one famine in the USSR, partly caused by kulaks burning grain. There were dozens of famines under the Tsars.

The same goes for China, there were dozens of famines under the emperors.

Communism ended famine.

Were those famines caused by poor political decisions? Possibly, but both countries were emerging from feudal subsistence farming, and had been ravaged by bitter civil wars. The position they were in meant even a single poor political decision could have caused a famine, if we were in that position today, with the leaders we have, we would all be dead.