Even though traders might not be tech savvy in a programming sense, what I've seen of a Bloomberg terminal (briefly, I'm not a trader) is that it's largely keyboard driven, with something similar to a command line, for the same reason that programmers prefer to use the keyboard and command lines: because it's an efficient, powerful use of muscle memory.

Also, it's monospaced, for the same reason programmers want things to be monospaced: because that way anything can be tabular data.

The article the GP linked is just wrong. People aren't opposed changing the terminal interface just because they're masochists. They're against changing the terminal because they have learned some powerful skills with it, and the "Web 2.0"-looking replacement that the designers are proposing has no equivalent of those skills.