Then propose a different definition. If we define it as "people uses it to organize family gatherings", then instead of YouTube you have iMessage, Discord, heck

Then propose a different definition. If we define it as "people uses it to organize family gatherings", then instead of YouTube you have iMessage, Discord, heck even SMS and email. The challenge here is there isn't a single market definition that would fit. It's up to the plaintiff (FTC) to allege a coherent definition, and it sounds like in this case they just neglected to do so.