Done correctly, reviewing papers is a tedious, time consuming & utterly thankless job that takes time away from your own research. Papers also often go through

Done correctly, reviewing papers is a tedious, time consuming & utterly thankless job that takes time away from your own research. Papers also often go through 2 or three rounds of reviewing/revision. Each one of these cycles can take 1-2 months so it's not surprising it's a slow process.