I'm not so sure... some people jump into Twitter without knowing much about it. If they "meet" the wrong people at the beginning, they may adopt behaviours that those noisy and spammy individuals think are ok, without actually being comfortable with them themselves.

Sometimes, you're a douche because you're a douche. Sometimes, you're a douche because you don't know better (yet).

I don't see much of it as "douchebag" on Twitter, obviously there's some who are just playing the numbers game etc, but Twitter is obviously also an effective marketing tool.

Using Twitter to make money isn't really the same as being a douchebag. Of course for users at the receiving end, it's irritating, but you can't blame people who have flocked to Twitter to promote and market.

or can you ?

I never understood this mentality, how is it ok if it's for promoting/marketing purpose ?

how is making money always ok ?

I didn't say it's ok, I'm just saying it's not necessarily 'douchebag' behavior, if Twitter is setup in a way that makes it very attractive for marketing/promotion.