Great scene that demonstrates how easy it is to influence sentiment.

Well, opinions can't be wrong no matter how many people disagree with you. Facts on the otherhand....

Facts are stupid and/or stubborn things.

Opinions can sometimes be wrong if they espouse illegal, immoral, or unethical behavior, right?

Wrong-headed if they are based on bads facts. I hadn't thought about the others.

If I am in the 50's and I think I should be able to sit in the front of the bus which is illegal, I'd say that might be a valid opinion. I can think of several issues where non-adherence to a law or civil disobedience might be called for, so there are good examples of opinions that espouse illegal behavior.

So maybe illegal and immoral or illegal and unethical.

Illegal being the key trait that makes them wrong.

In a jurisdiction with strong free speech protections, like the US, opinions are never 'wrong' in the sense of being subject to legal punishment -- not even opinions advocating illegal actions (except when "inciting or producing imminent lawless action and… likely to incite or produce such action").