By FAR! "That's the internet" is the real explanation of this.
When I get annoyed at this kind of stuff one of my best friends always tell me "don't be a little bitch"... And it's true, since the very beginning of the internet as we know it there has always been harassment, the only opinion about yourself that matters is yours.
And really if you get annoyed at this, you can always choose not to use this software. Same way you choose not to go to /b/. Don't be entitled to make the software work for you, and likely Twitter makes more money from trolls than from whiners.
I don't know if it's a culture thing but you guys (mostly west coast people) have a very thin skin and just take yourself way too seriously.
Guess what? I found all the comments funny and entertaining.