Problems can arise on any site. Whether or not you have a license does not matter that much. There are also sites in good standing that do not have an official gambling license, or at least do not withhold this information. As long as a gambling site pays the players, I don't see the problem of not publishing a gambling license and/or company details. But not every site is the same of course. This site has been around for quite some time, it is certainly not a new site.
But their past has been littered with ugly scam accusations. I think you can be able to see some of these accusations documented on their trust page. That alone should deter anybody from trusting the casino with their money.
The casino being around for quite some time should not blind someone into thinking they can be trusted 100%. Try telling that to the people who have been wronged by them.