The key piece of information you are missing from that article is that table game hold is typically NOT calculated the same way as slot hold because individual wagers are impossible to track on live tables.
Table Game Hold = Amount of chips won by the table / Total Chips Bought x 100%
Slot Machine Hold = Amount of money won by machine / Total Amount Wagered x 100%
So table game hold depends on not only the house edge, but the average amount players buy in for, and their average amount of time at the table.
If you would examine slot machine hold like you would table game hold as: Amount of money won by machine / Total Amount Fed into machine x 100% then you will find hold to be higher than the house edge. Most states don't calculate this, but Illinois bars and restaurants do. For September, the hold for slots there with this measure was 25.68%.