So each person must be wise enough to filter the truth from the bullshit and not judge the validity of what is said based on the speaker's skin color, social status, education, religion, ethnicity, political party, etc.

Just use logic and common sense.

So many people will agree to something simply because it supports their agenda even if they don't believe it themselves.

Or they are afraid to disagree with what what the majority believes because they might be perceived as stupid. Group think. The bandwagon logic. The Emperors new clothes effect.