Unironically, skill issue from their part. Slackware has an installer that works and unlike Debian is not a fucking fossil and it's practical: you can install "muh proprietary" components with zero issues and it's not driven by freetards.
Debian is dogass just like modern Windows: the fact that you unironically suggested to install Debian with GNOME says a lot, really.
GTK apps suck donkey dick, QT programs actually work and respect X11's DPI settings and scaling settings, see
the following blog post.
It is true that Windows is used for kiosks and such and its also true that I've seen those crash a few times due to Windows failing with cryptic error messages.