Read it like: "any amount of gambling may lose you money". The damage is proportional (and to some extent probabilistic) to the amount. As opposed to say: "any amount of horizontal speed may put you into orbit", which is not true ofc, there's a floor below which you will come right back down. Its a distinction between something which has non-zero levels that have no effect and something where the effect scales all the way from 0. It's a statement about populations obviously, diagnostics have finite precision etc etc, but it holds true as far as we know.