Starmer being an ideologue is a pretty funny take. I think most people would say he failed because he's a technocrat with no descernible principles or ideas.
Diversity over everything. Does not care about anything else. He is not a technocrat, to be a technocrat he would need to have evidence based policy, which he clearly did not. He is a pure, single minded, ideologue. Every event, every opportunity was just a conduit to express his single mindless slogan of diversity being our strength.
This is a weird take, because Starmer hasn't had a particularly pro-diversity agenda. His government has been harsh on immigration ("island of strangers", large drop in net migration) and has been quite happy to do nothing in the face of a court ruling making it essentially impermissible for trans people to use public toilets.