The Lineker analogy is about as stupid a thing as I've ever read.
GMB, whilst not a politics show, is very popular and influential within its demographic. Having a senior politician being interviewed by her husband is as big a conflict of interest as it's possible to imagine - worse imo than a Tory MP interviewing a Tory MP, even though the latter will clearly have political advantage to gain from it. They're married for fucks sake, any balance or criticism can be easily struck off as choreographed over breakfast. Absolutely terrible editorial decision making.
The comparison to footballing allegiance is just a nonsense.
I know politically there's no such thing as impartial. It's impossible to be knowledgeable about a subject like that without having preferences and dislikes. Whether it's Neill or Ferrari or Maitlis or JOB, you know who are they are or what they stand for but at least they're career journalists