That has been the constant refrain by ThirdWays against Progressives. It's called "propaganda". You shouldn't fall for it.

Progressives are actually very pragmatic. Our goal is making life better for most Americans. To do that, we must convince people that we can do that. Since most of the issues we propose to achieve that goal are supported by 60% to 80% of the American public, we believe running on those issues will help us achieve our goal.

Third-Wayers are also very pragmatic. Their goal is making money. Those popular issues are opposed by the people with money. Since Republicans are already opposed to those issues, it doesn't hurt us to oppose those issues too. We can concentrate instead on other issues on which Americans are more evenly split. So we can pay higher wages to campaign consultants, DNC staff, lobbyists, etc.