Nope you cannot consider them Young because they have been here for years now and proven their legitimacy .
I guess he was highlighting the sports betting section on Stake which was recently introduced which is why I agree him in this case.
There have been a lot of mentions of it through the gambling section and I think you've missed it. They're very known not just in crypto gambling but in the mainstream who's been into sports betting for a long time. Anyone can switch and use them if they want to.
I've seen some of the forum members who have experience in using them.
Am a Pinnacle user myself for sometime now and have pointed out on many occasions that it is easily one of the best sharp sportsbooks out there. The only con related to it is the KYC part in my opinion.