I'm saying that human nature is such that no ideal we pursue is ever fully attained; yet we do our best by pursuing the ideal. "Equality before the law" is an ideal; and as such, it's no stroke against it if you say, "Well, we haven't got there perfectly." That's the point: we need to work harder at it, and the more equal we make the law, the better we'll be.
Interestingly, even the empirical objection "People are not being treated as equal before the law" presumes that they SHOULD be. (If not, it's no objection at all, right?)
Socialism is a different issue, but let's speak of it here, since you raise it.
We can discuss it conceptually or historically.
Historically, it has resulted in gross injustices, many derived from its conceptual preference for the collective over the individual. In Russia, for example, if you were declared an "enemy of the State," you were essentially treated as guilty until proven innocent, because it was presumed that harm to the collective was bound to be much worse than any harm the State could possibly do to an individual. Of course, this put an unjust and unmeetable burden on the individual, so not surprisingly, Russian gulags were full.
That's not justice, obviously. But our objection to that arrangement is founded on the supposition that the individual or minorities do, in fact, matter, and the collective is not always more important, and certainly not automatically right -- an anti-Socialist supposition.