I think they don't really care about their citizens doing any aid. Or, basically, they care so little they're not willing to put their necks out first.

I think (well, hope) we're seeing a slow gathering of momentum as different countries make various small shows of support. If a dozen countries decided to send military escorts, and defended the aid all the way to its delivery into the people's hands, it would work... but right now, none of them are willing to step up and say that they'll do it by themselves. We'll see a bunch say they recognize palestine, then diplomatic attempts to get aid in, then rabble rousing about aid needing to be delivered... and in each step it'll be one followed by a few others before a larger amount all follow along. It'll take far too long, but I would say in another year and a half that there would be military escorts, as long as trump doesn't (threaten to) kickoff world war three.