The thing is gambling sites normally do not allow 1x. The closest you can get on PD for example is x1.012. On KINGDICE the maximum win chance you can bet with is 98% so it gives you x1.01 but never 1x. The Kelly strategy doesn't work for gamblers otherwise they would be all rich.
Sorry, I should have been clearer: My comment was addressing the investors, not the gamblers. "1x" refers to the simple Kelly criterion, not going for a 1.00x payout.
For the gamblers all wagers have a negative expected value. Consequently, the Kelly criterion will also always be negative, which means the optimal strategyin terms of bankroll growthis not to bet at all.