[IronKettle]

Silly in the sense that it's considered an unforgivable offense relative to how mild it actually is (in the realm of "ways you can screw up your life and others"). It's the staunchness that makes it silly.

If my sister cheated on her husband, I wouldn't stop talking to her forever or kick her out of the family (to the extent that I have that power). I'd be disappointed and it would affect our dynamic, sure, but it's not even close to a shunning offense.

Thinking on it, there's actually relatively few things she could do to warrant that kind of treatment.