While no one can be unbiased, we're all influenced by our own preferences, including critics, critics will tend to be proper cinephiles. They'll judge movies passed on their artistic merit, performances, technical elements etc. A critic's judgement is based on how good the product is.
Audiences will judge it purely based on their enjoyment of it. It's why The Last Jedi scores differ so wildly. On a technical basis it is a good film, but the audience, which for the majority consists of fanboys (and girls), who don't like the direction the story took.
I'd like to think so, but it feels like film criticism is becoming more ideological and they're unable to leave their personal beliefs behind and review a film objectively.
I think most people agree that The Last Jedi's was a poorly written mess full of decisions that betray established character's personalities, nonsense that renders most of the villains as buffoons, a completely pointless subplot and things that simply conflict with basic science like gravity. It was technically brilliant, I fully admit that, but so were most of the DCEU films (minus Wonder Woman) and they suffer from many of the same problems that The Last Jedi has, yet they all hover around 25%-50% at Rotten Tomatoes.
I actually gave Last Jedi 3.5/5.
I don't mean to be disparaging if you enjoyed it. One of my best friends is a HUGE Star Wars fan and he liked it quite a bit.
I've always been more of a casual fan, which is possibly why I look at it little more favourably. My two friends who are proper SW freaks though both hate it.