[bretthopper]

One explanation behind increasing polarization could be the internet.

I would assume that there are more movie critics now, or at least critics are more visible. Thanks to sites like Rotten Tomatoes, even a local newspaper critic can have global reach.

Due to this visibility, it's harder for critics to stand out. The easiest way to stand out is to be extreme or contrarian which would lead to more polarization.

[tpz]

Your point is a very important one that I was surprised to find was not expressed by other commenters. It convinced me of something that was bouncing around my head while reading the article and the comments before yours:

If, as everyone seems to agree, movies are becoming more 'safe', more 'lowest common denominator' on average, reviews should be becoming _less_ polarized in response, not more.

That the opposite is happening suggests that reviews are progressively carrying less and less 'truth' than they once did, and this is likely the case even when they may be in general agreement on a given film.