It's not surprising that there would be namespace collisions given the thousands of programming languages there are out there and the limited number of "cool" names available. I suspect someone at Google could have merely consulted http://en.wikipedia.org/wiki/List_of_programming_languages and decided that "Go" was free.

That said, I still find it inexcusable that Adobe's over-the-top PR machine has stolen the name "flex" from a well-known open-source lexer generator... mumble mumble....