pandering to AI companies cost them votes.
They got a lot of VERY negative media coverage for their stupid proposal to let the AI companies just take all the copyrighted work they wanted for training data for AI, with the creators and owners of that work allowed to opt out later, if they could figure out which of the secretive AI companies stole their work and convince them to remove it (while the AI companies made it clear they'd consider that too much trouble, and they wouldn't compensate the creatives, either).
Labour was pushing for much more use of AI by government and business, too, which does not get a lot of votes when there are already serious problems with the economy.
And Labour was pushing construction of data centers. From the Times 2 days ago:
Sky-high electricity prices threaten Labours AI revolution
https://www.thetimes.com/uk/politics/article/electricity-prices-threaten-labour-ai-529ccxwxv
Democrats really can't afford to be pro-AI, either, if they want to be seen as on the side of the people vs corporations.
(Which, again, is a reason why it looks bad for DUers to post and praise AI slop.)