I like the choice of words there, by the way <grins> ... "wuzzy left opportunists" I mean ... terminology like that reminds me of the good/bad old days.
For good measure though may I suggest adding something like, "These left-wing opportunists cover themselves with progressive phraseology, but push the masses to adventurism, and the party to sectarianism"? Or perhaps accusing them of revisionism and deviationism as well?