I don't know if the players were murder hobos (someone had to explain that to me!) in games they played before I joined but they're definitely not in EotE.
http://1d4chan.org/wiki/Murderhobo
"The term arises due to the fact that most adventuring characters and parties are technically homeless vagrants, generally living on the road and sometimes in temporary accommodation, and the default solution to problems faced by the typical adventurer boils down to killing things until the problem is solved or treasure is acquired."
Personally, I only use the term in jest, or if the players in my group starts to look at the game too much like a game without really considering the implications of their actions.