I think there's some confusion in this thread.
Mao's essay "Combat Liberalism" is about the practice of individual revolutionaries. Liberalism is defined essentially as being unprincipled. He discusses 11 instances of liberalism. Anyone who's been involved in political work long enough will recognize what he's talking about.
SovietPants posted a link to the essay. I highly suggest people read it. It's very short. Here it is again:
http://marx2mao.com/Mao/CL37.html
Mao's essay has nothing to do with being for or against "free thought," which Marxists would argue is just as much an ideological concept as "free market".
"I learned during [the fight against the colonial war in Algeria] that political conviction is not a question of numbers, of majority. Because at the beginning of the Algerian war, we were really very few against the war. It was a lesson for me; you have to do something when you think it's a necessity, when it's right, without caring about the numbers." - Alain Badiou