Back in the day, the commie bogeyman was used by LKY to scare Sinkies into submission and remove those who would challenge (or be perceived to be a threat to) his power. Catholics were Marxist conspirators, Chinese school students were communist sympathizers, unionists (the real ones, not the NTUC scums) were front groups for communism.
You get the idea.
Even in the late 1990s, LKY came out guns blazing and accused Tang Liang Hong of being a 'Chinese chauvinist'. I think everyone should know what he was insinuating.