Credit to @bontchev
Blog commenter Frank Wilhoit made a now somewhat famous assertion that the human default for nearly all of history has been conservatism, which he defined as follows:
There must be in-groups whom the law protects but does not bind, alongside out-groups whom the law binds but does not protect.
He then defined anti-conservatism as opposition to this way of thinking, so that would be to ensure the neutrality of the law and the equality of all peoples, races, and nationalities, which certainly sounds left-wing in our current culture. It would demand that a legal system which protects the powerful (in-groups) while punishing the marginalized (out-groups), or systematically burdens some groups more than others, be corrected or abolished.