I can admit that I am very harsh with the casinos that do not have an announcement thread on the forum as I am basically treat them as if they do not exist.
There must be a few good casinos out there that do not advertise on the forum, but since there are so many scams casinos out there I am not taking any risk and I gamble only at the casinos which have a thread here as if something happened to go wrong and I did nothing wrong I know the community will back me up, and the pressure we can generate together will be enough for the casino to do the right thing, as most casinos are not willing to ruin their reputation over something so small like a disgruntled customer.
I think a lot of people, including me, can relate to this feeling that you have, and it's a fact that this forum has a very big influence on almost all the projects since the forum has a pretty large audience and no project including casinos would ever want to lose their customers that they've got from this forum.
There's no doubt that there are good projects that might not be available on the forum, but as you said, now after spending many years on the forum, one would feel uncomfortable using a service that isn't available on the forum, it almost doesn't feel like we should trust them with our money as anything could happen.
It may seem odd that in a market where decentralization is supposed to be one of its main features I decide to almost only consider the casinos which have an ANN thread here, but when we take the time to take a look at the casinos which do not have an ANN thread here we can see that the percentage of scams is way higher.
Why should I take a risk and increase my chances of being scammed for no reason at all? And I simply do not find a satisfactory answer to that question, which explains why I avoid those casinos.