why do catholics say there is no salvation outside of their catholic doctrine?

The Catholic Church does NOT teach that there is no salvation outside of their doctrine. They do teach that people in other denominations and even other religions can get to heaven, although the typical way is through Christianity and the Catholic teachings.

The correct phrase is, "there is no salvation outside of the church" but to understand what it means you need to understand the concept of "church" as the body of Christ. Therefore all this means is that those who seek God genuinely will be brought to an explicit faith in Christ and receive salvation.
https://en.wikipedia.org/wiki/Extra_Ecclesiam_nulla_salus

actually its the protestants that say that

When was this said and who said it?

orthodoxy is the only true faith. all who reject mark of the beast will save their direct ancestors from hell (according to vyacheslav krasheninnikov). reject mark of the beast (usually given with world passport by isotope rays) at all cost. forgive me.

see this...... http://www.gotquestions.org/five-solas.html#ixzz3QjeI1pzr

Fear is their primary doctrine. Who would be a Catholic if they thought their was any other way of being saved? Evidently not very many or they wouldnt make this claim.

I guess they no better than the Son of God. Oh wait He didn't teach that either!

Ohh, let me guess.........is it because THEY CAN'T THINK FOR THEMSELVES??

To shít you up.

because that is that their doctrine says.. it is no different the MUSLIMS saying essentially the same thing.. if a person is not a Muslim then he/she is an infidel and should be killed.

Because they want your money.

They dont actually say that. Correct: "No salvation outside the Catholic Church"

If the Catholic church is the one true church, them salvation cannot be found outside of the church. It doesn't mean non-catholics can't be saved and go to heaven.

The Catholic church teaches if you believe and put your trust in Jesus along with displaying your goods works of your faith -- you will be saved. It just makes it easier if youre a part of the Catholic church since they observe the sacraments, etc.
Many Protestants do this. No suprise.