Well, its Twitter. What were you expecting? You ride on their network for free, you can't be surprised when they opt to kick you off it without warning. Yes, the courtesy would be nice, but...
Perhaps what's most galling is that, without users creating good content (users like the original @towerbridge) twitter would be nearly worthless.
"You ride on their network for free" as if users were leeching off of content twitter itself had made, when it's possible to just as easily argue that it's twitter who is leeching off of its users.
Musicians will often credit their "fans" as vital (e.g. [1]). Great music is still great even if only heard by a few people, making the fans impact at best indirect. Yet in the case of social networks, users and their participation are all the network has, period.
Set up a website.