O'Brien's takedowns of government policy and hypocrisy are very eloquent but it's mostly theatre. He doesn't really care about the things he's railing against or else he'd actually support those who are calling for change, and have been for a long time. He's a poster boy for people who aren't particularly liberal in their views but are desperately embarrassed about it and want to be seen as such.
Most of the stuff this government is doing is simply building on legislation and rhetoric which originated decades ago with the Nationality and Immigration Acts of the 70s and 80s, had a little resurgence in the early 2000s under Blair, was carried forward by Cameron and May and which would be Labour policy again under Starmer. The main difference is that this government have no qualms about the fact that it is indeed far-right policy.
That creates a problem for a certain kind of "liberal" because they suddenly have to pivot to attack policies they didn't care about or maybe even endorsed previously in order to maintain a veneer of progressivism. They've tried to sell it by engaging in this bizarre pretence that what Patel and Braverman have done is somehow fundamentally removed from Blair's raft of anti-asylum legislation in the early-2000s and proposal of a point-based immigration system in 2004 and from later stuff like May's hostile environment as Home Secretary under Cameron.
One of the reasons the likes of O'Brien are so obsessed with Brexit is because Remain vs. Leave becoming a shorthand for progressive values vs. conservative values gave them an easy out from that obvious hypocrisy. This is how we ended up in this bizarre situation where people like Alastair Campbell, Rory Stewart and even Theresa feckin' May who spent years in politics supporting draconian border policy and spewing right-wing rhetoric suddenly emerged as centrist heroes whilst people who spent years protesting against detainment of asylum seekers were being accused of being anti-immigrant.
Unfortunately, by saying he wouldn't repeal half the current government's legislation, Starmer has put that sort of liberal in a position where they have to really come up with some bullshit to justify flipping again.