why does the Catholic Church deny they say Salvation is only in their church?

Not surprising ...............however I do not need the Catholic Church to tell me how I get salvation, all I need is Gods word the Bible.............it was the Catholic church who have disrespected Gods name is so many ways especially when it comes to there trying to hide Gods name Yehovah!

Pay constant attention to yourself and to your teaching. Persevere in these things, for by doing this you will save both yourself and those who listen to you....1 Tim 4:16

1) Why does the Catholic Church deny they say Salvation is only in their church?

Logically impossible.
If the Catholic Church denies that it says that, then it doesn't say that.
If the Catholic Church says that, then it doesn't deny that it says that.

You CAN"T have it both ways as described in your question. That is: what your question claims CANNOT be accurate.

Me: Fundamentalist Christian

If you are saved it is by the Church of Jesus, you are interpreting this as if you had to know this consciously. Well you should if you are able. But a recently baptized baby does not.

Why does the CC say that non Catholics can go to heaven?

I don't know if you've noticed it or not, but EVERY sect and denomination of EVERY religion says that they know and practice the only way to salvation, and that everyone else is wrong. Did you really not know that about the religions?