This is one (sad) illustration of how Twitter is so unique a communication service, because of its particular access-control details. The fact that it's so hard to block/stop abusers is a consequence of the way Twitter leaves communications "open" and loose...with Facebook, you can't stalk/directly-abuse someone without them giving you some access (or revoking Facebook's default access). With email, you can target an address, but you can't read what's sent from it unless you're an addressee...Twitter is an open river for people to sample, and piss into. One of the things that the OP rips Twitter on is actually kind of a nuanced issue, IIRC. Twitter removed the "block" because "blocking" someone gave the blocker a false sense of security...you can never hide your activity from a stalker who simply logs out and views your public timeline.

"Block" effectively does nothing...what Twitter should've done is label the button something like "Ignore"...which would allow you to never be notified when that user sends a direct reply or mentions you...but would not have the same connotation as actively blocking that person in the way that a restraining order "blocks" someone.

As much as Twitter is seen as a superficial surface, nothing more than a dumbed-down micro version of blogging...the technicalities that underly its open nature is something that is hard to grok until you actively use it. I remember the "aha" moment for me was reading the report of when Demi Moore, an early Twitter celebrity, responded to a random person's suicide threat...just sending someone famous such a message would be impossible on Facebook, and pretty difficult on email (even if you knew the address, people/spam-systems are trained to filter such random messages out)...but in Twitter's early days, you had a decent chance of your crazy message being seen by just about anybody. That's the magic/insanity of Twitter for you.