Catholic's believe the Church is guided by the Holy Spirit through the magisteriun and consensus patrum are the "teachings of Christ" which are also made up of the Church Fathers , thus, we have set dogmatic teaching on much of this to protect the flock from error
Those outside the Church read the Bible and decide what teachings of Christ fits their own agenda.Sometimes you get it right and sometimes you don't.There is not set united teachings to adhere to,it's like ...In the words of Frank Sinatra ..."I did it my why" theology
The Church also teaches that our separated protestant brethren "Churches"are "Christian communities" and do not call them Churches since we believe in one Church
Wrong on both accounts and condemned already.
EVERY believer ONLY has access to faith through God. Not another mediator except Jesus Christ. Any human who adheres to a doctrine OTHER than directly from God, falls into the same category of picking and choosing independent of God.
Faith comes by hearing and hearing by the Word of God. The spiritual gift of Pastor-Teacher is a spiritual communication gift for some believers to communicate with others.
It is possible for a body of believers with such a gift to organize and group together doctrines through faith in Christ and provide them, communicate them to other believers as sound doctrine. It is possible for a RCC to perform this task.
It is also possible for any believer to remain in fellowship with God through faith alone in Christ alone and God the Holy Spirit perform that very same work within the believer. The believer is to respond to the Holy Spirit by the protocols God has provided.
If the believer instead picks and chooses by their own agenda, even if they are Roman Catholic obeying the letter of the magisteriun, they have already fallen out of fellowship with God and are following their own volition vice that of the Lord.