Stefon Diggs doesn't get pass interference call, resists protesting publicly

What exactly qualifies as pass interference in today’s NFL?
Stefon Diggs is probably asking himself that question today after a no-call against the Lions that seemed pretty clear to the novice eye.
It was the third quarter, first-and-10 from the Vikings’ 36-yard line, when Case Keenum launched a deep ball to Diggs, who was flanked by Lions safeties Glover Quin and Tavon Wilson.
Diggs went up for the ball, and promptly had his arm pulled down by Austin, who was injured on the play.
Take a look:

Play on! pic.twitter.com/mq9ASxA0jg
— That Dude (@cjzer0) November 23, 2017

Diggs was mad at the time, but by post-game, he’d simmered down — if for no other reason than to avoid a sure-fine if he publicly voiced any protest of the call.“I think the refs did a great job,” Diggs said when asked about the officiating in the game. The crew called 17 accepted penalties in the game. “They always do a great job. They called their calls, didn’t call the calls or whatever. I always feel like they’re doing a good job. Today they especially did a good.”He was pressed on the issue with this question: You didn’t think you were interfered with on that deep ball?“Nah, nah. Come on now, interference? The ref saw it how it should’ve been seen. No interference on either call. They’re going to continue to do a great job. I respect those guys.”But there was this ….

As clock ran out, Diggs yelled at an official who pulled out his flag, then jogged after Diggs, pointing. I think a fine will be in order. #Vikings— Jim Souhan (@SouhanStrib) November 23, 2017

But we get it. Mum’s the word to the media.
The score was 27-13 at the time. The drive ended with a Ryan Quigley punt from the 31. The Vikings still won, 30-23. So, it wasn’t detrimental. But it was puzzling.
Vikings coach Mike Zimmer bit his tongue when asked about the calls throughout the day.“We almost lost our composure a couple times,” Zimmer said. “We study each crew going into the game. I told them that it could be like this today and they’ve got to play clean, smart football and I probably shouldn’t say anything else.”