IIRC the term Geewunner was initially used just to satirically criticize the whole "new bad! old thing I like good!" But then people took the term and ran with it. So, now the meaning is completely lost and people just use it in any way they want. Technically the whiney fans that don't want Bayverse to end and like to endlessly shit on Bumblebee are being the "geewunners" of their own generation.