I think it's a much greater stretch to pretend that this person's obvious political bias doesn't leak into the "fact checking" they choose to do - or not to do, which is kind of the bigger issue. They may "correctly", ignoring the philosophically charged issue of "correct", fact check a certain politician but choose to ignore a different politician's statements that would otherwise be noted as incorrect under the same or similar standard.
Sure, their personal political bias should put them up to a greater level of scrutiny; but it they can still fact check without bias.
So, have they?