When Jesus came to the region of Caesarea Philippi, he asked his disciples, "Who do people say the Son of Man is?" They replied, "Some say John the Baptist; others say Elijah; and still others, Jeremiah or one of the prophets." "But what about you?" he asked. "Who do you say I am?" Simon Peter answered, "You are the Christ, the Son of the living God." Jesus replied, "Blessed are you, Simon son of Jonah, for this was not revealed to you by man, but by my Father in heaven. And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven."
Well, now I understand your confusion, you have a bad translation. In the Greek, the first “this” that you have in bold is not there. Rather the verse reads like this....
Blessed are you, Simon bar Jonah, for flesh and blood revealed IT not to thee, but my Father who is in the heavens.
I notice that it is all the NEW translations that have it thus. Even the KJV has IT and not THIS.
The sentence is a non sequitor as you seem to understand it, for Jesus says I also say to you just a little further on so there is no question that Jesus calls Simon, Rock and is addressing him alone in that passage.