Catholicity is the exact opposite of the perpetual isolation, solipsism and irreversibly curved-inwardness of the ubiquitous individualism in hell; hence the irony of the title of Matt's video.
"All authority has been given to Me in heaven and on earth. Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit." (Matthew 28:20)
"But you shall receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth." (Acts 1:8)
"For He Himself is our peace, who made both groups into one and broke down the barrier of the dividing wall" (Ephesians 2:14)
"Worthy art Thou to take the book, and to break its seals; for Thou wast slain, and didst purchase for God with Thy blood men from every tribe and tongue and people and nation." (Revelation 5:9)
"After these things I looked, and behold, a great multitude which no one could count, from every nation and all tribes and peoples and tongues, standing before the throne and before the Lamb, clothed in white robes, and palm branches were in their hands." (Revelation 7:9)
And I saw another angel flying in midheaven, having an eternal gospel to preach to those who live on the earth, and to every nation and tribe and tongue and people." (Revelation 14:6)