If they didn't say it was randomly moving - then it would be the same as the hundreds of other scripted grid slots that didn't cause an uproar. The line is crossed when the game rules are wrong...
And yes, it's exactly to implement absurd volatility - way beyond what natural mechanics will. So much dopamine to get people to believe these wins are genuine and achievable... until they see the rather large hole in their wallet.
Yes that was my objection to Jammin' Jars, I'm sure it's operating within the regulations, but the rules as written remain, to this day, entirely dishonest IMO.
So in essence, the game is constantly presenting to the player, things that the rules tell you can randomly occur (i.e. is entirely possible), that in reality, is entirely impossible.
It's still there in the rules, and it's still telling lies.