It's actually the other way around. It pays lip service to Brexit and honouring the result but the party has clearly moved to backing a new referendum.
-He says he won't accept May's deal.
-he wants an election.
-Then a a Labour deal.
-Or at worst a negotiated Tory/Labour deal.
-If none of these are obtainable than a referendum.
This might seem a long way from an unambiguous anti-Brexit position. But...
-Without it he can't get a Labour deal.
-Tory/Lab talks are going nowhere.
By default then, Labour is backing a new referendum. They're just not shouting it from the rooftops. That might be poor/good strategy but it is the position.