I guess I would just observe that there really are no viable Democratic candidates who are "far to the left." None of them is advocating public ownership of the means of production. Even the most "leftist" proposals out there - the various Medicare for All concepts - are well short of, for instance, the UK's National Health Service.... and the UK isn't exactly a Communist paradise.
The "leftist" or "progressive" policies that have peoples' teeth on edge?
- Medicare For All - some form of federally administered health insurance, similar to Medicare, but open to the entire population - either in place of current employer-provided health insurance, or as an adjunct for people without that coverage. This (obviously) threatens the health insurance industry, which employs a lot of people. Now, many people would be needed to administer MfA - but undoubtedly fewer than are now employed, at financial firms (Aetna, Cigna, etc.), or in medical practices dealing with the myriad bureaucratic requirements of our current system. So...we would get a less expensive health care insurance system overall (yes, Medicare IS less expensive than the private sector, when one factors in age-related cost differences), with much less hassle for consumers (I've lived under both systems now - Medicare IS less of a hassle), at the cost of some middle-man employment in the private insurance industry.
Side comment on the health insurance industry: A principal reason that Americans pay more (far more, in most cases) for decent, but not particularly outstanding healthcare, than most other western societies is that we have a very large number of people in the "industry" - insurance company employees, medical office personnel whose function is to navigate insurance company rules, etc. - who earn nice salaries, but don't actually provide health care to anybody. Single payer systems reduce this overhead, potentially significantly. We're effectively providing "welfare" for lots and lots of financial industry employees (and ancillary people in medical offices) by maintaining a system with lots of complex, but unnecessary administrative overhead.
Regulation of the financial sector. This is the one that has Wall Street types sweating over Elizabeth Warren. Warren would pursue re-regulation of the financial sector that would, if she succeeded, look something like the structure that existed in the 1980s, before Glass-Steagall was rescinded. Commercial banking and investment banking would once again be separated, by law, which would mean that if investment banks chose to take risks that put them at risk of bankruptcy, the commercial banking sector would be largely unimpacted - and the investment banks could just be allowed to fail, with their stockholders taking the hit... instead of being bailed out by the federal government, because they are "too big to fail," which is really about protecting the commercial banking sector (your bank accounts and mine, our mortgages, etc.). Many of us believe that abandoning Glass-Steagall was a really bad idea, that what happened in 2008 is clear evidence of that, and that what happened in 2008 looks very like it may happen again in the not-too-distant future. Do we really_need_, or want periodic financial crises and collapses, as the cost of allowing investment bankers to take big risks with other peoples' money, to enhance their profits? Or do we want to protect the financial system, at the cost of constraining gambling (and potential large profits) in the commercial banking sector? Which of these approaches is "radical"? Which is "conservative"?
The "Green New Deal." This threatens the coal and oil industries, predominantly. On the other hand, if we screw around incrementally regarding a national move away from fossil fuels, and don't make a strong commitment to stop emitting CO2 as quickly as possible... well, I'm of the opinion that the implications of that are pretty clear. It's been years since we debated climate change on philliesphans, and I know that some were skeptical of the seriousness of the problem then. Several years later, we have more evidence - and essentially ALL of that additional evidence is on one side of the debate. If we kick this can down the road, we will not be able to deal with the consequences, as a society. In my view, when knowledgeable scientists characterize this challenge as "existential," they're not exaggerating. So again, is it "radical" to undertake a major effort here? Is it "conservative" to stick our heads in the sand?