Usually avoid making statements using the word "you." This means I'm addressing the subject, not the person. It creates a better chance of avoiding offending someone's ego.
Mostly prefer to use the response,
"I disagree," if it's a matter of opinion, ethics or values,
"that's not factual," if I can provide the proof, or
"that's not logical," if the thinking contains a logical fallacy.
Then I wait to see if they ask a question, which could indicate curiosity and willingness to engage in conversation.
If someone is fanatical about something, I take a deep breath and call up calmness and relaxation with myself.
If someone is completely uninterested in hearing a different response, I may ask them about how and why they hold the view they do, and try to explore as deeply as they will allow. That way, I at least benefit from learning something more about how people tick.
Blocking I would only do if someone was verbally abusive or inappropriate.
So far have not had the need to do that.
