Fair enough. I still find the whole thing questionable since KDE took quite a few ideas from Windows Aero.
It's irrelevant. Adobe gave their permission for that image to be used, the permission of the KDE developers asked. Usually I tend to find Linux developers are pretty good where sharing their creations are concerned. As for the other point you made... so what? Very few pieces of software as complex as a Linux window manager or operating system will be built without using some of the competition's ideas it's just the way computing works.
You still have to give credit and follow any other conditions of the license since there's different clauses for commercial and private uses, it's not a free for all and anarchy in the FOSS world, no matter what the media says
Understood, I understand the basics of how the GPL works but in truth I rarely read licensing agreements