Most people here agree with you that walking away is best, but I wonder if an alternative is equally as good. How about confronting the person gently and respectfully? Tell the person why what he or she is saying annoys you and give him or her a chance to learn from the experience and make a change?
I mean, think of the alternative: If everyone who gets annoyed walks away, won’t the only people left on the forum be the annoying ones? Who then would want to come to the forum when all they meet are annoying people who care nothing about encouraging others and helping hem learn? Also, what would visitors seeking the truth about Catholicism think of Catholics if everyone they met here was annoying and unhelpful, because all the encouraging and helpful Catholics were taking a break?
Years ago I came here to debate, when debate was more tollerated. While debating, I met some incredibly patient, kind and helpful Catholics whose actions impressed me even more than the truth of their words. How they treated me had a lasting effect on me, and opened my eyes to the possibility that I wasn’t as right about things as I thought.
Just a thought…