It also hard (impossible) to do bait and switch like sellers do on amazon.
I believe IMBD can help you identify the "most popular" movie. But it's up to you to decide if that's a good indicator for quality.
To give you an example, look at the top 10 songs in Spotify worldwide and tell me if those songs are the "best" songs the art form can provide.
After going deep on an art form, being music, painting, sculpting or film making, you start to develop a taste and an appetite for more complex expressions.
What would you prefer, votes of 10 people that have watched over 1000 films or votes of 1000 people that have watched 10 films?
The TV show "King the Land" is a Korean drama that aired on cable in Korea this summer and was released at the same time on Netflix worldwide. It was very popular in Korea [1] and many Asian countries. But if you look at IMDB [2] it has a 4.2 rating, with 116 thousand votes of 1/10. Similar Korean shows typically have ratings in the 7-9 range. The reason for the low rating is a controversy over a minor character in the show. I don't know how this mass voting was organized, but it seems to have worked in affecting the IMDB score (and similarly on RT).