That is because Catholics have been saying that over and over and over again.
If a lie is said enough times, some will believe it.
Each Christian has the Holy Spirit as a guide into all Truth.
Therefore all those that are born again believers in Jesus will be of one mind on spiritual matters.
Your comment:”Therefore all those that are born again believers in Jesus will be of one mind on spiritual matters.”
You really believe that?
The protest religions seem to continue make their own interpretations of the Bible. i.e. marriage and divorce, abortion, female clergy, same sex marriage, homosexuality, the Real Presence, etc?