Explanation

While tells you that the clause after the comma will oppose the clause before the comma.

So instead of “supporters,” you want “opposers.” The word condemned further hints that the first word will be something like “opposers/condemners.” Only detractors works. For the second word, you want a description that a detractor would apply to “earthy speech.” So you want “earthy, but in a bad way” — perhaps “coarse” or “unrefined” would serve. The word vulgar fits those descriptions. “common.”

Detractors, vulgar.