Why do some people believe that Catholics aren't Christian?

Why do some people believe that Catholics arent Christian?

They are. In fact, they were the very first. It even says so in the Bible (i. e. "And I say also unto thee, that thou art Peter, and upon this rock I will build my church" - Matthew 16:18). St. Peter was the very first Pope.

Why do some people believe that Catholics aren't Christian?
Post Opinion