Because you side against the blockade because you either don't believe the Israeli reasons why the risk of not blockading are serious enough to warrant something as harsh as a blockade, or you just don't care about the consequences for the Israelis either way. The former is far more complicated than a casual observer could know offhand and the latter is obvious one-sidedness which speaks for itself. Take you're pick.

FYI: The food restrictions were never of a nature that would cause malnutrition, that is propaganda. If you know even a bit about the issue you know the Israelis have reasons for blockading construction material, so the question is if you are neutral, why you don't believe them.