crazyjz,
first of all you must be asleep at the wheel to not know that kettleholes can lso be formed in bedrock. you can see them today in any bedrock river reach. the normal explanation is that trapped stones eddy and grind out deep circular holes. with sediment-laden subglacial water and trapped boulders, Browning Lake is just a scaled-up example of the same thing.
secondly, you are wilfully misunderstanding the sources cited. Somehow you fail to understand that there is no transport without erosion. In the "cjz" model subglacial water can transport sediment but magically can not erode? How odd.
In the absence of subglacial water, as you note, deposition dominates and till builds up. Deposition is in fact the opposite of erosion so this is not a very convincing mechanism for your claim that subglacial erosion is a significant process in the absence of water. I realize that you don't deal with this much in petrology, so your confusion is understandable.