So I guess that's the basic problem "Christans" have with "Catholics"? Catholics pick and chose what they want to believe and preach? (And also, don't Christians have a problem with Catholics worshiping statues and stuff?)
See my Biblical Christianity message board. A thread up at the top happens to be about that very issue.
Also, for a contast between Biblical Christianity and Roman Catholicism, this site has several helpful, readable essays. Start with Slide 1 and Slide 2 towards the bottom. Then you might want to read the testimony of the RC priest who ended up leaving Rome for Jesus.
Dan