Incorrect. The one form of leverage they have on the ratchet is choosing between the spinny part and the still part. Every vote for a Democrat is a vote for the still part. Every vote not cast for the still part is a willful gamble on the spinny part.

Both parts are bad, but the spinny part is worse and getting worser. Electoral leverage has a fairly narrow and unambiguous scope, and for anyone on the left who doesn't have the luxury of RCV or competitive third parties, that leverage is best applied via BNMW.

Other forms of leverage (local elections, workplace unionization, direct action) are highly encouraged, but beyond the scope of elections. Those other forms of leverage will be more productive under the lesser evil than the greater one. Every vote cast for a Democrat (excepting districts where third parties are competitive, obviously) is a vote for the most favorable achievable conditions to effect other forms of leverage.