I think this is more a matter of course when you don’t have the internet. Correct ideas among generally aligned people are more important when you’re already generally aligned, Lenin’s target audience wasn’t really right-wingers.

It’s an artifact of time, you see constant leftist infighting even now, because it is easier to get impassioned about people who mostly agree with you than it is to get impassioned about people entirely divorced from your worldview and conclusions.

Having a main target doesn’t mean you don’t have other targets, and refuting incorrect ideas is important when belief in these ideas is what holds a movement together and allows it to preserve its revolutionary character. When you have an actual movement out there in the world, you can’t just be ambivalent about the positive aspect of your theory so that everyone can hold hands and get along. You need to organize a certain way and not others, just as you cannot sail a ship simultaneously in two directions. Lenin and company were completely correct in trying to correct the course of their respective ships.