Shruti
So what's the story where Vinayak doesn't block his father from getting home?
Normally, while everyone sympathizes w/ Vinayak and even hate Shiva for beheading him, at least Mahadev had a good rationale: this person from nowhere was blocking him from entering his own home, and refusing to hear reason (well, there they could have made allowance for the fact that he was a kid). Yeah, it's extreme that after he routs all the devas and ganas, while he's battling Vishnu, Shiva beheads him from behind. But here too, one can at least rationalize it that losing to a kid made everyone lose their mind, and they ganged up on him and killed him by crook.
But in this story, everybody has gotten to see Vinayak and welcome him. Now, if Shiva goes on to behead him, it'll be irrational. At least, in the above case, he had a rational, if arguable, reason for beheading him, but here, he won't have any. Unless they show him beheading Vinayak by accident, which too is there in some accounts.