You must have worked with some pretty bad designers in the past to have that much contempt for them.
And what I see is often a contempt for the designer-ignorant layman.
All the usual caveats apply: what I say is not applicable to absolutely, no exceptions, 100% of designers, but mostly to the particular subculture/demographic we talk about here: Western/US designers from the young/urban/hipster population (which makes for the majority of those of them posting their opinions on design issues on the web).