Why is tolerance so difficult?

[sarisataka]

While participating in this thread http://www.democraticunderground.com/?com=view_post&forum=1002&pid=7143004 I encountered some quite venomous replies.

While I am Catholic, many of my in-laws are Native and follow Traditional beliefs. I have no issue standing at a Pow Wow when the benediction is given, even though I do not believe in Animism. I would no sooner touch an eagle feather without permission than any of my relatives would snatch the Host from the priest's hand at a mass. It is simply a sign of respect as a guest.

I have no need to challenge their "primitive" beliefs and they do not try and tell me I am a foll for believing in a "sky fairy".

Yet some people seem offended to their core knowing that I have a differing personal belief. I don't get it.