I think you are getting a few things confused in my opinion. There are minimum standards on what it means to 'complete' a lift. Then there are a few cues that you need to do to execute a lift with 'good form' (by whatever standards you want to use). I'm not a coach, but most people would agree that to make the lift (DL as in your example) with good form you do so with a neutral/flat back (not rounded) - I'm over simplifying for sake of argument. I've looked at PL standards and no where does it state that you need to use 'good form'. You have one minute to walk up to the bar, pick it up, and stand up straight, then put it down with some semblance of control. If (as you state) there are disagreements as the the validity of the lift, I guarantee the disagreement is on COMPLETION of the lift rather then PROPER FORM. I've never seen a PL DL disqualified for not keeping a flat/neutral back. In your video example, sure he rounds his back, but that is not related at all to the standards for the lift (Crossfit or PL). He's simply missing a cue and not a movement standard.

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Related to pull-ups - I think you need to accept that they are two distinct exercises. Strict pull-ups and kipping pull-ups. Don't conflate them. They are different. A kipping pull is just that, a kipping pull up. It is not a strict pull-up with bad form. If you choose not to do them, ok fine, but don't not do them because you think it is bad from/cheating/dangerous.