Those are just tutorials showing how to install something. Typing flatpak install firefox is one and the same as going into the app store, searching for Firefox and clicking “install”. Tutorial websites would just show terminal as it’s more universal.
If they ask you to actually download some file there is something very wrong.

I often see people overwhelmed by universality of some things. Instead of searching “How to install Firefox on Linux?” what should be learned is “How to install software on Linux?” and, unless met with something badly ported, never do the search again.

But what my meme is about is Windows-only style of having some file and by default having no idea if that’s going to run in some program or be a program.