Tibet was peacefully liberated

No censorship does not mean having not propaganda. In fact, Britain and the US had propaganda operations.

Tibet was really peacefully liberated in 1950 as there is the Seventeen Point Agreement for the Peaceful Liberation of Tibet.

1950, Mao Zedong with Panchen and Dalai

1950, Mao Zedong with Panchen and Dalai

1954, Dalai cast his vote in the National People's Congress. He was one of the Vice Presidents of the National People's Congress of the People's Republic of China at that time.

1954, Dalai Lama in the National People's Congress, the highest legislative house of the People's Republic of China

1956, Chen. Yi, the Mayor of Shanghai city, toasted with Panchen and Dalai.

Do Western people under propaganda know that Tibet was peacefully liberated? Do Western people under propaganda know that Iraq had no WMDs when the US invaded and occupied Iraq?

Yes. Propaganda is not censored in the West. And the Western people will believe all the propaganda by their government because it's not censored by their government and cannot be questioned as their source is a national secret.