BTW, you probably want to move off of uM given gorhill has abandoned it in favor of uBO. (I converted all my rules to a mix of uBO dynamic rules for JS and static rules for everything else, except for cookies which I still use uM for because uBO can't manage them.)
BTW, the site works as expected with my Linux/Firefox/uMatrix setup... the inline scripts are disabled by default and I see the page content. I'm not sure why GP had issues.