Totally up to you, whatever costs you are aware of.
I feel similarly, though I don't put it to others in such a slightly aggressive way as "Why do you feel --?" Personally, I have pre-shunned a few people out of disgust. I have also been shunned by some old friends and family members without being DFed. I discovered a few "friends" who I didn't mind losing once they showed their real selves.
And ultimately, that's a price I needed to pay. The benefit is freedom and understanding and individuation, rather than indentured servitude.
Soon, I plan on getting together with cousins and an aunt who were CUT OFF from my family decades ago. I'd also love to see more family members whom I've never had the pleasure of meeting. Family goes beyond the immediate, and even in my immediate family, I don't believe I would be entirely judiciously shunned at this point.