I read your response to "Why did Catholicism start and when did it happen?" But you did nothing to refute Catholic claims. You just repeated them. The question also makes no sense. "Why did Catholicism start?" - because it is the teaching of the apostles.
"When did it happen?" It happened as soon as the side of Jesus and His Sacred Heart were pierced. John tells us specifically that water and blood came out to symbolize baptism and the Holy Eucharist.
Perhaps it is because the questioner didn't ask why Roman Catholicism was wrong. He was interested in when it occurred. But the refutation is there, though you don't realize it. The fact that Roman Catholicism has changed over time is evidence that it isn't the church established by the apostles. Roman Catholicism wasn't taught by the apostles. The fact that current beliefs started after the days of the apostles demonstrates this fact.
John mentions the fact that water and blood came from the side of the Savior (John 19:34). It is not a symbol but the actual event. Nor does John connect these to baptism or the Lord's Supper.
"Then the soldiers came and broke the legs of the first and of the other who was crucified with Him. But when they came to Jesus and saw that He was already dead, they did not break His legs. But one of the soldiers pierced His side with a spear, and immediately blood and water came out. And he who has seen has testified, and his testimony is true; and he knows that he is telling the truth, so that you may believe. For these things were done that the Scripture should be fulfilled, "Not one of His bones shall be broken." And again another Scripture says, "They shall look on Him whom they pierced"" (John 19:32-37).
The purpose of recording this fact was so that we would have greater faith in the prophecies of God.
Baptism represents Jesus' death, burial, resurrection: "Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life. For if we have been united together in the likeness of His death, certainly we also shall be in the likeness of His resurrection, knowing this, that our old man was crucified with Him, that the body of sin might be done away with, that we should no longer be slaves of sin" (Romans 6:3-6). Yes, blood and water came from the Savior's side, but baptism is not a representation of this one event -- it is much broader.
The Lord's Supper is a memorial of Jesus' shed blood and his broken body. "For I received from the Lord that which I also delivered to you: that the Lord Jesus on the same night in which He was betrayed took bread; and when He had given thanks, He broke it and said, "Take, eat; this is My body which is broken for you; do this in remembrance of Me." In the same manner He also took the cup after supper, saying, "This cup is the new covenant in My blood. This do, as often as you drink it, in remembrance of Me." For as often as you eat this bread and drink this cup, you proclaim the Lord's death till He comes" (I Corinthians 11:23-26). Like baptism, it reminds Christians of his death, but it is also a reminder of much more.
The name "Holy Eucharist" is not found in the Bible, let alone applied to the Lord's Supper. The name Eucharist is derived from a Greek word meaning "to give thanks." While we give thanks to God for the sacrifice of His Son while partaking of the Lord's Supper, the covenant meal was not called "Eucharist" by God.
If you are interested in a refutation of various Roman Catholic beliefs, I would direct your attention to other pages on this web site, such as the articles on Roman Catholicism.