Light is the best disinfectant, but cockroaches scurry under the fridge when you flip the switch, figuratively speaking. That is to say, exposing a group of liberals for the crazies they are is a good idea, but they have ways of hiding from scrutiny. How to combat this?
Here’s a little idea for you: make efforts to link moderate leftists with radical ones, especially the ones that sound crazy. For example, there was, at one point, a group of white people who went to Jamaica to march around wearing manacles and collars while wearing shirts that said “So sorry” on the front (not making this up – Google it). There are photographs of this. The idea here is to juxtapose those images (photographs of the ‘so sorry’ people) with more moderate or socially acceptable Leftist activity. Suppose one took a quote from a professor who does some social-theoretic nonsense work on race, superimposed it over images of the ‘so sorry’ people, printed it out on fliers, and distributed it around a campus where said professor was scheduled to give a talk? It gives a rather ridiculous association to that professor’s work, effectively dampening their influence. This is only one example, but it’s a particularly good one because it doesn’t come across as right-wing propaganda. Those fliers could easily have been printed out by an overzealous social justice activist!
Another example of this kind of thing, to get your creative juices flowing: if a feminist journalist has said something a bit “hasty” in the past, you can make an effort to associate everything she says with that quote. Suppose further that said journalist has said or implied that it is morally acceptable for a woman to assault a man for reasons besides self-defense (there is a popular Jezebel article that does this, with strings of delightfully over-the-top agreement in the comments section). Go ahead and find one of her new articles, enthusiastically “agree” with her, and casually bring up said dirty laundry. “Your remark about how monogamy is intrinsically oppressive is spot-on! Anyone engaging in monogamy is not a true feminist.” This also helps to drive the entire Left toward a more radical position, which is what we want, in order to create a backlash.
A third example: trolling moderate leftists (esp. journalists and academics) by chastising them in the guise of a more radical leftist is a great way to embarrass them, because it drops them into a catch-22: either argue against the more radical wing of their movement (necessarily forcing them to appeal to non-Leftist principles) or agree with the craziness. If they do the first, you can alert some more obnoxious SJW types to said person’s disagreement; one link on the loonier parts of Tumblr can trigger a hysterical dogpile on the person in question, which ratchets up the pressure and helps splinter the Left via internal strife. If your target instead responds by agreeing with the crazy statements you’re making, you can then spread the word far and wide that [name] agrees with [insane statement].
Remember, this all works on the principle that the Left survives by dealing with people piece-meal. A moderate leftist will repudiate the more extreme fringes of their movement in front of dissenters while agreeing with it in private. The way to break this form of evasion and nail them down to what they earnestly believe is to make the craziness stick to the moderates.