Every statement in the above comment is wrong:

People born in the 90s wouldn’t have a chance to be old enough to belong to any group other than a preschool before the collapse of the Soviet and Soviet aligned regimes.

For those who were adults before 1990, while they may have been party members for reasons unrelated to political ideology, it wasn’t as common: in the late 80s, only ~10% of adults in Warsaw pact countries were communist party members. Far from “everyone”.

And even if you check that in the DS-160 visa application form, you are allowed to add an explanation. Consular visa officers are very well familiar with the political situation at the countries they are stationed in, and can grant visa even if the box is checked.