I;m confused. The Palestinians claim to be a nation. Israel builds a border wall, and that's 'apartheid'?
I believe the "apartheid" is a reference to how the Palestinians are treated as second class "people" I guess as they aren't citizens - for example they don't have autonomy over planning within the small amounts of territory they control even as Israel can just overrule and demolish, in plenty of other Palestinian areas Israel oversees things rather than the Palestinians.
As for a border wall, that would be much less of a problem, this isn't a border wall but rather it is a security wall that is designed to encompass various illegal Israeli settlements too and cut through and encompass Palestinian land - this is an obvious problem as the Palestinians would eventually like to end the current "apartheid" situation and have their own state, this is somewhat harder when the territory that makes up that state is cut up by security walls, patches of Israeli administered territory because of settlements etc...
Those settlements are a major problem with regards to ever sorting the mess out.