Because most anime fans don't go to imdb to vote on anime, they go on myanimelist, where Monster is sitting around 325k members/110k votes. Lion King is to movies what Monster is to anime.

I mean, the top rated anime has ~660k votes with ~1 million members. The top rated TV show on imdb has 43k, and only really Breaking Bad and Game of Thrones have a large number of votes of all of the top 10 shows.

So as I originally said, laid out in simple terms:

Users of imdb(movies) = users of myanimelist(anime)

Rank #48 735k votes(movies) = Rank #48 110k votes(anime)

It's definitely smaller, because obviously "movies" has a bigger audience than "anime", but it's not like they're vastly different numbers. It's not like you're comparing the numbers for the NFL Superbowl vs. the numbers for the recreational women's basketball tournament, it's more like you're comparing numbers for the Superbowl vs. the Wimbledon Finals.