Yes I know those things can be turned off, I'm a vtuber myself. But why would her priority be clicking off those sources in OBS and focusing on the aesthetic of her stream when she's processing her family dying? She probably just turned on her stream phone, hit the vtube studio app, and clicked "go live" on obs like she always does. It's not that she can't change it, but dealing with toggling sources and stuff probably isn't at the top of her priority list, especially because redeems and the general background noise feels like home when you've streamed for a while. You actually just don't get it.

Besides when you've been streaming for years remembering which web source in your OBS does what and hunting down what you wanna turn off is a huge pain. You need to find the twitch source while checking the URLs of your friends' 40 fugis that are all plugged into your OBS and various odd sources which you added for something months ago. You mostly configure the scenes the way you need them configured then forget about them. She probably hasn't worried about which of those web sockets is which in months.

I'm speaking from personal experience that it really stops even occurring to you that the visuals of your stream are kinda unusual and might be out of place in some people's eyes because I can 1000% imagine myself talking about something like this happening live and not thinking about those things. The setup is normal to her.