Disagree. It was a textbook penalty according to that rule. Josh already sliding when the defender dips his head and puts his forearms into Allen's upper body.
For comparison, watch the Rudolph slide where Klein is already lounging at him, but makes the necessary adjustment to stay over the top.
People have too much time on their hands to be complaining about non-issues.
It's like @Zerovoltzcomplaining about a non-existent fake slide. This stuff is so stupid.