Because the revelation was done in private. Then the private individuals made it public.
Contrast this with, say, the Pentecost, where the Apostles were filled with the Holy Spirit while spreading the word!!! Jesus would be a good example of public Revelation, wouldn’t he?
I wouldve thought that the evangelising of the apostles was more of a public reveleation than the Gospel Jesus was spreading, even though the Apostles continued the message of Jesus anyway. Jesus came to save the Jews first did He not? This verse springs to mind:
Matthew 15:
21 Then Jesus went thence, and departed into the coasts of Tyre and Sidon.
22 And, behold, a woman of Canaan came out of the same coasts, and cried unto him, saying, Have mercy on me, O Lord, thou son of David; my daughter is grievously vexed with a devil.
23 But he answered her not a word. And his disciples came and besought him, saying, Send her away; for she crieth after us.
24 But he answered and said, I am not sent but unto the lost sheep of the house of Israel.
25 Then came she and worshipped him, saying, Lord, help me.
**26 But he answered and said, It is not meet to take the children’s bread, and to cast it to dogs. **
27 And she said, Truth, Lord: yet the dogs eat of the crumbs which fall from their masters’ table.
28 Then Jesus answered and said unto her, O woman, great is thy faith: be it unto thee even as thou wilt. And her daughter was made whole from that very hour.
www.biblegateway.com
But anyway I think you’re more right here than me. So what would happen if the children of Fatima were commissioned to spread the message? Doesnt that message become public revelation