Is there a good reason for Shudder.com being blocked? I am thinking of trying it out and want to know what issues there have been with it that prompted a hard block of the entire site by Comcast.
I can reach the site. When one customer cannot reach a site but others can, it usually means the site is blocking that customer's public Comcast IP. You can look up your IP at https://www.google.com/search?q=IP. You'll probably need to ask the site's admins for help with this.
@Vando22 wrote: ... if that were the case I wouldn't be able to access the site when disabling protected browsing ...
You hadn't mentioned Protected Browsing. In that case I suggest contacting Comcast Security Assurance at 1-888-565-4329 (from https://internetsecurity.xfinity.com/help/report-abuse/) and asking them to remove the site from the Protected Browsing block list.