I have an older 8GB MacBook Air. This is false. I routinely have Slack, Chrome, iTerm, Visual Studio Code, and more open on it. It’s fine.
Those apps don’t need every single byte of memory you see in Activity Monitor to be active in RAM all of the time. The OS swaps out unused parts to the very fast SSD. If you push it so far that active pages are constantly being swapped out as apps compete then you start to notice, but the threshold for that is a lot higher than HN comments seem to think.
It really isn't. It is a capable machine but modern software has made it a lemon. And that is the only reason apple sells it. So that whoever buys it needs to buy another one prematurely, generating another sale.
Everything from apple to modern software is rotten to its core.