I've watched many videos including that one. It also shows wear and damage/flattening to the teeth (comments pointed this out in that video). The Cobra teeth are soft and will flatten. I've confirmed it multiple times (on multiple pliers) gripping anything that is harder than soft metal (brass/copper etc). Channellock's, Bahco's and others didn't have this issue.
Did you watch that video? He makes a point to say some of the black finish wore off but that the teeth are undamaged. And the Irwins definitely had issues in both videos. Any teeth will flatten if subjected to very hard material or abuse, but from everything I found the Knipex was overwhelmingly described as doing very well in the face of hard-but-typical use (which is what both of those videos show, and others I watched but won't take time to look up). My experience is the same so far - I've used both pairs I own a fair bit and they're both in completely fine shape.
Describing the Cobras as soft is definitely incorrect, at least relative to the Irwins. The Irwins cost less, so it's not fair to compare them 100% to the Knipex. (I was actually trying to justify buying the Irwins when I was doing all that research btw)
I'd always thought of Bahco as an adjustable/Crescent-style maker, and only found their water pump pliers just now. The reviews on Amazon are pretty good (4.4 on 28 reviews), but not better than the Cobras (4.9 for the trad. style with 3,739 reviews and 4.8 for the comfort style with 376). I'm sure Bahco is fine, but if the Cobras were soft, they'd suffer in the reviews. I tend to take reviews on Amazon with a grain of salt in a couple ways, but directionally there aren't any warning flags for Knipex there either.
As for the Doyle, I'll wait to hear some real-world reviews on it. Frankly, the premium for the Knipex doesn't point me to Harbor Freight - for less than ten bucks more I'm getting a completely proven high-quality tool.