"uke attitude" is the fanatical attitude adopted by most true ukulele players. This mainly consists of showing the superiority and general coolness of ukuleles compared with any other musical instrument, especially guitars.
Anybody with true "uke attitude" refuses any non ukulele ways of playing the ukulele: plectrums (or plectra?) are absolutely forbidden, as is Low G tuning. On the other hand any slightly (or very) weird techniques such as tapping (best done on an electric ukulele) or playing with the teeth are to be encouraged, because this enhances the weirdness factor already present in anyone who even thinks about ukulele playing as a good idea. So basically one of the main aspects of "uke attitude" is that desire to be different from everyone else and feel superior about it.
The other main aspect of "uke attitude" is to treat anything involving guitars (although this does not include bass guitar) as belonging to the dark side. Liking music with guitars in is not prohibited, but thinking seriously about actually playing guitar certainly is! Of course, pretending to want to explore new horizons and picking up a guitar, playing a few notes and deciding it is definitely not for you does not qualify as "thinking seriously about playing guitar", and is therefore actively encouraged in "uke attitude".
The band that best illustrates "uke attitude" is of course the Ukulele Orchestra of Great Britain. An all ukulele band who play a variety of styles. On the CD cover of their album "The Secret of Life" they claim that "from the point of view of ethnomusicology, a guitar is merely a genetically modified ukulele with extra strings". In France there is the the Ukulele Club de Paris.