I really like the sentiment you have expressed here and I do subscribe to a very similar attitude. I actually find myself engaging with a lot of people I disagree with here on steemit and I view this as a positive thing. Staying inside the echo chamber of agreement indeed offers limited opportunities for growth and questioning things alongside somebody with a totally different perspective allows for a deeper understanding of your positions as well or even replacing your faulty positions with more reasonable ones.
Still, while I try to be accepting of other people's opinions, there are things that I can't chalk up to simple disagreement and there are ideas and views that I find repulsive. If I find something like that I disengage and I don't mind breaking friendships with people who hold despicable positions for despicable reasons.
I haven't come across despicable opinions from my friends yet, but you're right, there are going to be people that argue things that you find intolerable.