We can be critical of the mistakes of past socialist systems without falling into the trap of believing every red scare era lie about them.
Not defending past socialist systems' accomplishments makes current socialists look like absolute cucks.
Winning the rhetorical war cannot be done if you stop to qualify every single thing you advocate for by disavowing every society that has ever advocated for that thing. The USSR was the most equal society that has existed on this earth since the industrial revolution, and served every one of its member countries better than they are served by their capitalist successor governments today. Meanwhile, basically every person who has been lifted out of poverty in the past thirty years has been Chinese, proving that socialism fucking works in a way that capitalism doesn't, even when both systems contain markets, wage labor, and an investment class.