Labour were not an anti-Brexit party in this election.
Their policy was to negotiate their own 'better' deal with the EU, and then hold a referendum on that deal. They refused to commit in advance whether they would support their own leave deal or remain in the subsequent confirmatory referendum.
Anyone attempting to claim that Labour were an anti-Brexit party, and then using that to argue that a majority or plurality of voters voted for anti-Brexit parties yesterday is either misinformed, deluded, or lying.