Except that isn't correct. Kyle Reese is John's father, period. It is a time paradox; the future that Kyle Reese comes from is one in which Sarah Connor has already had his baby in the past. The photograph of Sarah that he swoons over before ever being send back is the one that he himself took of Sarah in the past.
John Connor would be two completely different people if "some guy" was his father in one timeline, and Kyle Reese was his father after being sent back.
I think the latter is exactly what he was trying to suggest.
In other words, the original "untampered" timeline has Sarah give birth to John via an unknown father. In that timeline Skynet takes over, then tries to use time travel to screw with the past, so "John A" sends Kyle back to stop it. Kyle winds up boning Sarah, so she gives birth to a completely different version of John with different genetics, personality, personal history, etc.
So THAT John ("John B") lives through the new timeline, which is now different. When he meets and recruits Kyle, he recognizes him as the man who will eventually be his own father, and thus takes the actions we hear about in the first movie (giving him the picture of his mother, causing him to fall in love with her before they even meet), then sending him back in time to save her/become his dad. In THIS reality, because events are different, Sarah basically winds up giving birth to a THIRD different version of John ("John C"), and we've effectively wound up in what looks like a stable time loop.
Then T2 basically implies the time loop is anything but stable, John C's future winds up being completely different from either John A or John B.
There aren't separate timelines, there is no John A, B, or C; it is one jacked up loop. That's what it means to be a paradox. John only exists to send Kyle back because Kyle went back to father him in the first place. The entire reason Kyle has the photo of Sarah and is the one chosen by John to be sent back in time is because John already knows from Sarah that Kyle is his father, there is no unknown father. ---