~snip~
It's possible if he plays along, it's fine after all. He created a casino company because he understands how to play.
Besides, why is he playing, because his casino company is already making a profit? Possibly playing just for fun.
The analogy is the same as a director who takes part in a film, he does it because he is happy and passionate about it.
Unless you have lost a lot of money there, maybe you feel you have been cheated by the owner who is playing.
That sentiment can be true and we really don't know what will be the truth behind as the owner have their rigth to play if they wanted to test the system that they bought or they ae paying for, and aside from testing their own platform they also have that side where as human they can also try to play to be entertain.
You are right, unless you already lost a lot of money so thinking about bias outcome or manipulated outcome can show up when you know that the owner is playing using their own casino.
But when we really observe in detail we will find the answer that there is no reason that can be known for certain as to whether casino owner plays or bets in his own casino.
Let think carefully, the casino owner must have lot of experience and knowledge in the gambling industry, including how every existing casino works or develops, even his own.
If it for fun, of course he has lot of experience and also business partners so he would prefer to play directly at the table with his colleagues instead of playing on the site he owns.
If the reason is to test their own platform then that is not necessary because the progress can be seen from how enthusiastic each customer is, even each casino has system for handling or running the casino well and the casino owner can find out from there.
There is an uncertainty that is really difficult to predict so some people might have bad thoughts when they find out that casino owner is playing or betting in his own casino.
Moreover, there is lot of thinking like this among gamblers and many people think excessively as you have said.