Catholics do NOT insist that. Get your facts straight.

I consider myself a Christian, not a Catholic. Catholics may believe in Christ but I was brought up separating the two.

Generally most Catholics no longer believe this sort of thing. Back in the 1960's in keeping with the spirit of the times, the Church changes its policy on Protestants in the second Vatican Council. Previously, they emphasised the differences between Catholics and Protestants but since then the emphasis has been upon what both groups have in common. Traditionally. the RC Church has believed that it it was the one "true" church founded by Jesus.Anyone who rejected this supposedly rejected Jesus. Very conservative Catholics used to refer to the parable of the Prodical Son or the story of Noahs Ark. The Prodical son supposedly represented Protestants, the good son Catholics and the Father, the Church.In Noahs Ark, the Ark supposedly represented the Church, Noahs family the Catholics and those who drowned the non-Catholics. Nowadays, this is considered to be bigotry and a sin.Protestants are considered as Christians who differ on some details of Christianity. The Church line is that they are the best Church, but that other Churches are nearly as good. Even non-Christians are supposed to be in with a chance of salvation, but their chances are said to be less good than in the RC Church. Protestants have gone from being God cursed heretics to fellow brothers in Christ.

Some would suggest that many Catholics are heretics. Jesus, for example. :P

Lots of christian groups believe that they are the only true church, and everyone else is wrong. This isn't limited to catholics. Within those groups, there will always be extreme individuals who believe that other groups are inferior or whatever. Again, not a catholic thing, but a human thing.

Jesus called Peter 'the rock on which I will build my Church'. Catholics work on two assumptions: 1. That this means Peter was given leadership and 'the top job' shepherding the new Church, so you have to follow what he says in order to be doing it right. 2. That Peter went to Rome and selected his own successor and that the chain of successors (ie the only men on earth to have God's approval to run the Christian church) are the Popes. On that basis the ones that are sticklers may not question your belief in Christ, but they will question your association with the 'one true' church, and therefore your credentials for redemption & salvation.

1. they don't think they're not cristians, they just think that they're not catholic. 2.they do not think that they are heretics, just broken off from the pope. 3.by "salvation" if you mean heaven, the metaphor is that catholics have all of the tools needed to get into heaven, while christians only have a few, but non-catholics may still enter heaven.