"Mama Susan" is a nickname given to the CEO of YouTube, Susan Wojkiscikiski windows 78 or some shit. The nickname "Mama Susan" is generally used by the YouTube commentary community and is used to describe her company's strict and inconsistent stance what gets to be monetized content.
Much like how your mama would have strict rules and unfair regulations, Mama Susan's YouTube is notorious for demonetizing creators who make legitimate content whilst allowing nefarious creators who constantly abuse the YouTube guidelines to thrive.
Mama Susan's reign has often been agreed upon to be one of the causes for the death of edginess on YouTube due to creators fearing their channels to someday be obliterated for mild substandard behavior.
"So what Susan Windex has done is allowing scam channels to continue their reign whilst striking down channels with legitimate content"
"Sounds like Mama Susan alright."