Maybe he could see that these people all receive the same salary they did at Facebook until they can find another job? No idea how the math would work out on that, but that seems to be the kind of "taking responsibility" that would actually be meaningful.

In a case like this, I don't think the point should be whether Zuckerberg "would actually feel" a consequence: it should be whether the people getting laid off—as in, the ones who were wronged—can feel it.