"We have not endorsed or approved the VidAngel technology" is a lot different than "The VidAngel technology breaks our (Netflix's) Terms of Service and we will be taking legal action."
If innovators and market disrupters waited to make their innovations public until they had permission, I'd be typing this on a typewriter or sending this via telegraph.
There's a very simple and straight-forward argument that VidAngel is NOT "insert[ing] any code or product or manipulat[ing] the content of the Netflix service in any way." Netflix and Amazon Prime know this, which is probably why after five years of the new VidAngel, these streamers have not taken legal action.
I suspect you know this too.
(***I do not and probably never will subscribe to VidAngel.)