I always find people who hold overly strong opinions a bit suspect. They present their opinions as fact, yet only a handful of beliefs can receive validation as truths. Most things in life are open to interpretation, and interpretation is mostly a subjective exercise. No one person has all the answers or a full understanding of the facts.
When you entirely ignore other points of view and refuse to listen to different ideas, you are inhibiting your intellectual growth. You don’t need to entirely alter your opinions, but they should withstand the rigorous scrutiny of logic and alternative viewpoints. Also, being louder or more emotional than the other person doesn’t make you right; it just shows you’re brash and indifferent to others’ feelings.
Passion is good, commitment is good, conviction is good, and courage is good. However, all these things, coupled with ignorance and/or a closed mind, are potentially dangerous.