You obviously don't.
Peter was given a duty which has yet to be fulfilled.
In your opinion.
You quite obviously aren't familiar with typology and I doubt that whoever reads excerpts from Scripture to you on Sunday or Saturday or over the TV has ever explained it but you would be well served to carefully and methodically reflect on Isaias 22:22 and Matthew 16:19. See if you can figure it out.
"And I will lay the key of the house of David upon his shoulder: and he shall open, and none shall shut: and he shall shut, and none shall open." Isaias 22:22
"And I will give to thee the keys of the kingdom of heaven. And whatsoever thou shalt bind upon earth, it shall be bound also in heaven: and whatsoever thou shalt loose upon earth, it shall be loosed also in heaven." Matthew 16:19
"And I will give to thee the keys of the kingdom of heaven. And whatsoever thou shalt bind upon earth, it shall be bound also in heaven: and whatsoever thou shalt loose upon earth, it shall be loosed also in heaven." Matthew 16:19
So hey, Carnac, explain this verse to us simpletons...A quick look appears that whatever Peter comes up with, good or bad, God has no choice but to accept it as being bound, the rule of law...And what Peter doesn't want bound, he can loose or remove...Is that the Catholic understanding of this verse???