I find that very few of Mao's critiques apply specifically to Liberalism. They are counterrevolutionary and harmful tendencies which should be shut down as soon as they are recognized, but I get the feeling that when this was written, Liberalism was not particularly established within China, and served more as a boogie man for what could happen if revolutionary discipline were allowed to deteriorate.

Essentially it is "Combat Liberalism by not presenting any opportunity for it to get a foothold."