Movies and books are created for an audience. That audience has a right to have an opinion on what's being offered and to express that opinion.
For me, the point of a critic/reviewer is knowing where they're coming from. I've used certain critics as negative indicators: if they loved it, I know I'll hate it, and vice versa. Still useful information. When I've found a critic/reviewer whose tastes (not expertise) I trust, then I will give their opinion a great deal of weight. I don't care what their background is.