@ndegruchy @mooshoe I don't know. If have to agree with them on this. It would be really annoying to maintain a GNOME app and have Ubuntu theming make it look weird by default. Not only does it make you look bad, but you also get probably get tons of bug reports for various themes because something doesn't work right. Then you end up focusing on making sure your app works with the theme of major distros.
They aren't calling out people for theming. They are calling out distros for theming.