Ther's a faq item about this issue: https://inkscape.org/en/learn/faq/#copypaste-rasterizes-obje...
There is no such thing as a polished GTK app. GTK widgets are really bad designed take for instance the `open` or `save` dialogues, only somebody how does not care about usability could come with that. Any application (no exceptions) made in GTK+ can be done better, faster in Qt through a much more polished and robust API. it's ashamed that inkscape is tied with such bad widget toolkit.
On Linux, it's vastly more usable, and quite polished for a GTK+ application.