The ICM is an equity model, not a strategy. What you are talking about is following the push/fold Nash equilibrium according to the ICM for isolated hands.
There are times to deviate from the Nash equilibrium.
-- You may have reads on your opponents. If they are deviating from the Nash equilibrium in known ways, then you should deviate.
-- Push/fold may not be the right way to play. It usually is in a super turbo or hyperturbo, though.
-- The hands are not isolated. If you know that you will hit the blinds next hand, your equity from folding is lower than the ICM predicts. If you know that you will get several free hands before hitting the blinds, your equity from folding is higher than the ICM predicts. This can mean you should use a small nonzero edge in a program like SNG Wizard.
However, the Nash equilibrium push/fold strategy is not going to lose anything close to 10%. I think that was just hyperbole by someone who overvalues the improvements on the Nash equilibrium, or who wants to discourage players from joining his games. In fact, most serious players do not play as well as the Nash equilibrium push/fold strategy.