A metaphor to mull over

The church had to keep its power. Thus supporting the nazis during WW2 and every other leading (military) power during the times. Thus the crusaders. Thus the denial of new theories.

This is misleading.The church of 1000 years ago certainly isn't the church now. If someone argues that because they have some of the same beliefs, they are still to blame, he would also be arguing that the British government is bad because of King John. And Nazis? Please. Does that mean the current Italian government is tainted by WWII?

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All you need to do is hold a stick above the horizon to see that the earth isn't as flat as the stick.

I'm confused by this statement. Please explain further?