The left thinks having good ideas wins, but the right understands that you win by winning. The right always wins on logistics, not philosophy or science. Leonard's Catholic conservative Platonic idealism is philosophically quite easy to refute, but that doesn't matter if those who believe in it are superior in their ability to mobilize. Words on a page or a screen do not in and of themselves accomplish anything.
I was reading another thread on the SF housing crisis a while back and as usual it was full of people bashing NIMBYs. Someone commented that NIMBYs keep winning in spite of the crisis they're helping create and even in spite of the fact that they're probably a numerical minority because they show up to meetings.
I've also been absolutely shocked by the online alt-right's capacity to organize. Beginning with Gamergate the online right has punched far above their weight in numbers when it comes to influencing the culture. I really do believe that the 4chan orbiting online right played a non-trivial role in Trump's election.
If you never ever organize you'll be the victim of those who do. Paradoxically some amount of collective action is required to secure individual liberty. The founders of America (who were liberals in their day) understood this very well. Today's liberals need to re-learn it.
Organizing requires a certain amount of conformity. That doesn't mean you have to completely submerge yourself in the group. It doesn't mean joining a cult. What it does mean is that you make the strategic decision to join in an effort in spite of not necessarily agreeing with absolutely every bullet point or liking everyone else who is involved. When a person joins the army that doesn't mean they like everyone in their country or even all the leaders of that country, but armies win wars while disorganized mobs do not.
If liberals (of any persuasion) are to have any chance whatsoever of repelling things like this, they must get over their aversion to organizing and forming groups and hierarchies. I think the major culprit here is the post-hippie cynical hyper-individualism that reached its cultural crescendo in the 1990s.
Another equally important factor here is that people like Leonard Leo are hard working, responsible, and dedicated. Sitting around and smoking dope doesn't win wars any more than always just fucking off and doing your own thing. Reagan famously quipped that he once saw a group of protesters holding a "make love not war" sign and thought they "didn't look capable of doing either." He was right. As sympathetic as I am to the potential mind-expanding uses of things like psychedelic drugs as well as to the human right to occasionally have fun, I've really come to believe that excessive drug use, drug advocacy, and drug culture in general is a major factor in the decline of the American left. Even those who don't use drugs are influenced by the mentality behind it. I've heard a lot of conspiracy mongering about how the CIA introduced drugs into the counterculture to achieve precisely this, but if that's true there's an easy way to defeat it: practice personal discernment and moderation and don't just get high all the time.
Edit: one last point about the Reagan quote: the left needs to listen to its right-wing critics on subjects like this. Only your enemies will tell you the truth.