Problem is we don't know if he is manipulating the numbers!
In the case he does NOT, I would NOT call this a scam since he still pays you the win.
I agree with point 3, he choose the complete wrong way to advertise his site!

To your conclusion that easily can be drawn without too much speculation:
Point 1 and 2 is what most casino's do.
All over the world they advertise massive jackpots and then when someone actually hits the jackpot they do everything to NOT pay it to you.
For example by simply saying the machine was defect etc.
Also as we all know it's more likely to get a few small payouts than one big one since the chance for winning the big pot is way lower.

So basically what I am saying is, that I do not agree with point 1 and 2 since most casino's do exactly the same.
BUT, I do agree with point 3, he should have advertised his site differently!