Note, however, that according to the passage Peter WAS already committing the "sin" of eating with Gentiles - i.e. he was acting in agreement with Paul -
before he succumbed to the human bigotry of other Jews, but then Paul set him straight. So that's far less support for your position than it might first appear, simply from the fact there was a some point something of a confrontation.
If it is not necessary to keep it then it is not a law, it is a recommendation.
According to modern archeology and the theological views that arise out of it, righteousness was NOT about "keeping the Law" since it was already recognized within 1rst century Judaism that no one did it well enough anyway. It was about an
cultural identity, about who could belong to the "people of God," the ones who were given the [Mosaic] Law. "The Way", then, was about expanding the cultural groups who could consider themselves "people of God". Rather than being focused on individuals and their salvation (as perhaps it was understood to be 1500 years later in Luther's very influential but eisogetical reading). And this view probably appealed in particular to Hellenized Jews and to those with "mixed" backgrounds of which there were many in the cosmopolitan world of the Roman Empire. "The Way", therefore, was a kind of internalized Judaism, perhaps. (Or, to cop a Deleuzian phrase, it was perhaps a kind of "deterritorialized Judaism.")
What Paul says, then, a number of times, is that these various cultural backgrounds are not so important and not of the essence of "Godliness'. (As when he says, "if you're a Jew, stay Jewish; if you're Greek, stay Greek" and so forth.) There's no particular righteousness in human cultures in Paul's perspective, which is really a pretty commonsense concept, imv. And similar in its common-sensical tone to many of Christ's essential, earthy, common sensical teachings, too, as recorded in the various Gospels....