A good break down of the other polls done by Yougov on this subject by youtuber Phil Moorhouse.
My personal opinion is that Labour do not want to talk about Brexit until they can stop the Tory media telling lies on the subject. We will only get one shot at reversing this fiasco, so they want to get it right. With Labour I agree on this. Let it lie until we can have some actual facts on the matter. Any discussions with current media throwing in their bias is swayed by those who have pocketed billions from the Misery imposed over Brexit.
tbf any time people vote for a party that fearmongers about foreigners it’s equivalent to them kicking themselves in the nuts, like at best it only results in yet more money being taken from the voters and put into the pockets of the wealthy