Now I know why I disliked shows like The Profiler.
Sure The Profiler had an interesting base-story line, but it seemed the 'filler eps' interrupted the story's flow. I know there needs to be more than just the main story, that there needs to be sub-stories that show, also, the other facets of a character's life, but there just seemed to be too many of them. Or that the filler eps seemed to simply ignore the main story line. Pretend it didn't exist.
Supernatural is doing the same thing.
Casual references to the pending apocalypse do not, in my opinion, constitute valid inclusions of the main story line. Eps that 'forget' about the main story line are just as bad.
What happened tonight in 'Jump the Shark' was a painful representation of the above.
I'm sure about 99% of the viewing audience knows a man like John does not suddenly become celibate when his wife dies/is murdered. Even a super-strong sense of vengeance does not eliminate the baser need for sex. In fact, it can increase it, sometimes exponentially, as a skewed way of reaffirming one's existence. ("I feel, therefore I am still alive.") So John had sex. Probably a lot of it. However, John most likely had protected sex. He knew about condoms. And he probably wouldn't even consider sex without them, so as not to introduce yet more offspring into a world whose nightmares are quite real. John had to watch his present sons-Dean and Sam-go through life like a pair of paranoid borderline schizos, behaving as though there were nefarious preternatural creatures around every corner. Even if John had considered fathering a child but keeping them ignorant of the world's darker side, John would have thought that sooner or later something would happen to shatter that child's innocence. Even if the thought were something along the lines of the child being a Winchester and therefore automatically a magnet for danger. Part of John's mind splintered when Mary died.
Therefore, the creation of this episode feels more like an insult to our, the audience's, intelligence, than any forwarding of the story line. There was nothing redeeming in this episode. What we learned of the boys-Dean's altering perception of John, and the relationship between John and Sam, and Dean's perception of that; the possibility of John attempting to live a normal life by taking Adam to a baseball game, and teaching him to hunt animals as opposed to unnatural creatures; and of the existence of ghouls-does not justify the existence of this episode. These are things we didn't need to be told, because most of us probably figured them out on our own, as the intelligent beings that we are.
Storytelling is about showing, not telling. But it's also about not 'showing' us what can be easily figured out on our own. The reader/viewer/audience does not like to be treated like idiots. This episode felt like a condescending piece of nothing.