Hang on, did you read the quote above from the guy that named it?! He says explicitly that he chose it not because it was accurate but because non-technical employers/funders would be unlikely to object since it sounds positive. Does that not meet your definition of "bad choice" for a technical term?

"dynamic programming language" means a "dynamically typed" language; and "dynamically typed" means the types are acquired at run time, and vary at run time according to run time events. So "dynamic" is a good choice there in that it is consistent with the use of the word outside programming.