Why am I unable to access certain US media content like NBC Peacock or social media pages (e.g., Instagram) of most US news outlets, but I can access most YouTube channels of American news outlets? Is this the same case for Americans—can they also not access certain Canadian media but can for others? What determines which types of media content are available or restricted for people in different countries?
Thank you for any input!
Your internet service provider (ISP) or network administrator might have set up filters to block certain types of content, like adult material, illegal content, or anything that goes against their terms of service. 
Media content access is often restricted by licensing agreements and regional regulations. The differences in accessibility between various platforms and types of content can be attributed to how these agreements are structured and the global reach of the platforms hosting the content.