if you look at the twitter profiles of people who tweet stuff about “taking back the labour party” from jeremy corbyn they usually also retweet conservative mps, use right-wing fearmongering about the labour left, never mention the devastation that the tories are causing, never focus on how to stop the tories, think that having a people-led movement to get the tories out is fascism, and frequently misrepresent what labour’s current policy regarding brexit is in order to sway voters away from labour. they’re not interested in actually stopping brexit or the tories, their aim is to get rid of corbyn and any leftist leaders.
there should indeed be healthy debate about ways to tackle brexit, but it’s become clear that these people are now using much of their arguments about brexit as just a cover to attack the labour left. aside from brexit, centrist/right-wingers are actually okay with 99% of what the tories have done to decimate the country that’s caused so much suffering. their actual issue has always been the leftist policies that a jeremy corbyn led labour party would enact. for them the left is a greater threat to their power than the conservatives.
that’s why the same people who say they can’t support labour because of brexit will still support blairite labour mps who abstained from voting against the conservatives’ welfare bill, or will vote for the libdems who formed a coalition with the conservatives and helped push through austerity. the same conservative party who called for the referendum in the first place.
these people don’t want to dismantle an unjust system, they just want to be in charge of it.