"It was painful because your wealth was really under fire last night," Cramer said on "Squawk Box." "How did this get to be, that if you're wealthy and you're a Democrat, it's just bad news? And I think that's a shame."
Sanders has emerged as the front-runner for the Democratic nomination after strong performances earlier this month in the Iowa caucuses and New Hampshire primary.
Ahead of Wednesday's debate, the Vermont independent nheld a 10-point lead in an an average of national polls. He also holds a 14-point lead in an average of state polls for Nevada, which holds its caucuses Saturday.
Cramer said that he thought Sanders sounded like a communist during the Vegas debate.
Sanders, a self-described democratic socialist, advocates more federal government control of the economy while keeping a political democracy intact.
He proposes a broad range of social programs including "Medicare for All," free tuition at public colleges, a federal jobs guarantee, alongside a wealth tax on the richest Americans and higher corporate taxes.
"Is he really a socialist? Or is he a communist? What is socialist about what he wants?" the "Mad Money" host said. "Isn't he more of a communist?"
Socialist models rely on government planning to drive the economy. Under communism, the state controls the economy and government, aiming to eliminate social classes.
Asked for comment on Cramer's remarks, Mike Casca, a spokesman for Sanders' campaign, said in an email, "How can anyone look at the massive level of wealth and income inequality in our country and say to themselves, 'Yeah, this is fine?'"
Bloomberg, a former mayor of New York City who is worth more than $65 billion, also compared some of Sanders' proposals to communism in his Democratic debate debut.
Third in an average of national polls, Bloomberg said, "We're not going to throw out capitalism," arguing "other countries tried that." He added, "It was called communism, and it just didn't work."
Sanders said he thought Bloomberg's invocation of communism was "a cheap shot."
The senator has compared his economic vision to Nordic countries such as Denmark. His proposal to give workers ownership stakes in companies is consistent with some ideological variations of socialism.
During the debate, Sanders said, "What our movement is about is bringing working-class people together, black and white and Latino, Native American, Asian American, around an agenda that works for all of us and not just the billionaire class."
Cramer said his takeaway was that the Democratic Party is "the party now of revolution and the Republican is the party of preservation."
"Revolution and distribution seems to be what people want in the Democratic Party," he said. "I don't recall this ever."
"What really matters here to me is trying to bring jobs back. I never thought that was a right-wing issue. So it was a left-wing issue that the right has kind of grudgingly adopted because the right wants profits for companies," the "Mad Money" host said at the time.
Cramer has also praised Trump's tax cuts for individuals and corporations through the prism that they are good for the U.S. economy and therefore the stock market, which drives investor wealth.
"They hate wealth so much I just cringe," Cramer said Thursday of the Democrats. "I worked really hard. I did OK. And I guess I'm supposed to be for another party."