With momentum building for single-payer healthcare among Democratic voters and a growing number of 2020 hopefuls, Sen. Bernie Sanders unveiled a “Medicare for All” bill last week. Immediately, a number of pundits denounced the legislation as an “unrealistic” “bloated” “disaster” full of “magic math.”

Some of the naysayers are conservatives who simply abhor “big government.” Some have perfectly valid reasons to question the merits of single payer in general or Sanders’ methods in particular. Yet others claim they support universal healthcare in theory (one day, perhaps) but cannot do so now because of a “concern.” They are “concern trolls” — broadly defined as “a person who disingenuously expresses concern about an issue with the intention of undermining or derailing genuine discussion.”