[grateful]

The rules have changed.

ARTICLE 8. INITIATING CONTACT WITH THE CROWN OF THE HELMET
It is a foul if a runner or tackler initiates forcible contact by delivering a blow with the top/crown of his helmet against an opponent when both players are clearly outside the tackle box (an area extending from tackle to tackle and from three yards beyond the line of scrimmage to the offensive team's end line).

Whether he's a defenseless receiver or a runner is irrelevant now. Current NFL rules call this an illegal hit.

[FredZarguna]

That’s the targeting rule, and that’s not what Shazier did. Quit the crybaby routine.

[cport]

You forgot the rest of it

It is a foul if a runner or tackler initiates forcible contact by delivering a blow with the top/crown of his helmet against an opponent when both players are clearly outside the tackle box (an area extending from tackle to tackle and from three yards beyond the line of scrimmage to the offensive team's end line). Incidental contact by the helmet of a runner or tackler against an opponent shall not be a foul.

Note: The tackle box no longer exists once the ball leaves the tackle box.

The ball left the tackle box, hence, no foul.