I guess he is looking at history, not sure his specific point. Liverpool a city I know very well due to family was the only city to go pretty much full Marxist in the 80’s, it’s about as anti-Tory as you can get these days.
It is also well known as the most Irish large city in the world outside of Ireland, beating both Glasgow and Boston. I think some estimates that 50% plus of the population is still of Irish descent although that also includes Protestant northerners.
Unlike Glasgow while it did have sectarianism in the past it never got like Glasgow which divided into Celtic and Rangers, Catholic and Protestant. Scouse bonds where stronger mostly than Glaswegian bonds but Liverpool was the proddie team and Everton the Catholic although that was a very long time ago which is not the case in Glasgow.