A couple YouTube tabs are enough if you leave them running for long enough. Just one YT browser process will easily take up 1-4GB sooner or later.
Or it won’t because Chrome and MacOS will know how much RAM is available and manage it effectively.
I am talking from experience with an M1 & 8GB RAM. I had to restart either the browser or the YouTube browser processes at least once every couple days to stop the whole system from lagging.
A couple Facebook Marketplace tabs that have videos of the item for sale would absolutely crush my 2017 MacBook Pro.
My M1 Air would slow down a little, but was still usable doing the same thing. And they both had 8GB of memory.
While I agree with your statement, I don't think judging one's way of working and using their computer was necessary.
I could have two browser windows open in the late 1990s. I have about a thousand times as much RAM now. So even with 10x more bloat in the pages, I should be able to open 200 tabs just fine.