So rather than disable the system tray, or use other applications that don't have inconsistent scaled and styled icons, you'd prefer that nobody who uses Gnome is able to have a system tray?
The first versions of Gnome 3 did indeed have a system tray for backwards compatibility, and it was hidden out of the way until you needed it. Eventually it was scrapped once enough software was updated to not rely on it.
If somebody insists on having a messy UI, they can use literally any other DE available for Linux.