Snap is very canonical centric. You cannot set up your own snap store, automatic updates are mandatory, etc. It's is for all intents and purposes a second Ubuntu repo with even stricter control.
And the general proliferation of Appimages, Flatpak, Nix, Guix, Docker containers, and of course local building of software all tell against the "using software from outside the distro's repos is discouraged" representation.
Of those listed, only AppImage is as easy to publish and install as your average Windows software (Flatpak is a not-so-close second with significantly more limitations). And then you get prominent FOSS developers like Drew DeVault saying that those distribution methods are terrible ideas because they are dangerous. The way things work in the Linux Desktop and its community are just not conducive to simply passing around software without middlemen the way it has been in real personal computing systems since the 80s.
You can make assertions like this if you like, but they're simply untrue. Windows is nightmare to install software on, while on Linux one usually has multiple, easy-to-install-and-keep-updated options (Appimage being the worst choice, because it is the most Windows-distribution-like, and requires the application itself to check for updates etc.).
You can also distribute binaries on Linux easily enough. There's just no general reason to want to do so.
