I don't think people in the UK do hate Russians. Many of us have a deep dislike and distrust of Putin because we believe, based on clear evidence, that he and the ruling Russian regime are a malign influence in the world but that doesn't mean we hate ordinary Russian people. I don't.
I've known a few ordinary Russians and they aren't really that different to you and I. Some were good people , some were OK and some were less so. As far as their political system and politicians are concerned you have to ask yourself if Putin & Co are any less trustworthy than our glorious leaders have been ?
a combination of media and home grown (in this case uk) ignorance. rather than research an area or topic, and why should they? unless they have a particular interest in it. most people only have time for what they are are told.