I could stay friends with them if we had a lot else in common. Friends are hard to come by and circumcising is a very popular mistake in this country, one that is usually made in a half-drugged and completely exhausted state, and one for which there is a lot of cultural pressure. I couldn't judge someone for believing a pro-circ doctor or clergyman instead of me.
The question I would be more likely to ask is: would they stay friends with me, after I interfered in their private business? There are some people that I gave info to, that went ahead and circ'ed, and now I get the feeling they're not comfortable around me anymore.
I have a friend who had her son circ'ed recently. I don't judge her because I know she had really low self-confidence in her parenting abilities, and her husband, who is a neonatologist, made the decision. Now, I'll make an effort never to have to be in in the same room with her husband again--it disgusts me that a person who knows how painful and unnecessary it is would do that to their child---but she is a sweet person and I like her a lot. I consider her a secondary victim.