Why do born again "Christians" deny the fact that Catholicism is Christianity?

It is an oxymoron when calling them "Christians". Walking in the shoes of Christ would indicate an unsurped level of tolerance and acceptance of everyone. Yet; "born agains" are believers in the religion of EXCLUSION. In other words, you must be like them, and be "Saved" through the born again process that they dictate(even after baptism), in order to gain your place in heaven. The idea to me that I need for some reason to be "saved", indicates that I am lacking in some way when compared to those who feel they don't need this process, or already have had it? If that is the case, then obviously "born agains" believe themselves to be superior to me in the eyes of God. It is akin to the Jews feeling they are "chosen". It is natural therefor to feel alienated, discounted, ostracized, and unliked when in their presence, and frankly; they are the most "non-Christ like" group of people one can encounter in organized religion.