This is not surprising, Lugar has been with his party leadership on this all along, including his letter in July that got the State Department to write their response that appeared to blame Zelaya for the coup. Honduras has become a real cause for the Republican party leadership, which sees it as a strategic battle in their long-term fight against the Latin American left (which for them includes Lula). Although Lugar is of course different from them, for some reason he has joined with them in this battle.
This has to be a disappointment to people who see Lugar as a moderate, since it is tough for a moderate to defend the position that a a group of people can overthrow the elected president, arrest, jail, and beat thousands of people, torture and even kill some people, close down opposition media intermittently throughout the legally designated 3-month electoral campaign period, and then have a valid "election" -- no matter how "clean" it is on election day.
Lugar's statement will give some lobbyists, pundits, editors, etc. some ammunition to say that not only the wingnuts that hold this position.
The State Department effectively has the same position as Lugar in what it is trying to accomplish, but for now is reluctant to state it unambiguously, so as not to further distance itself from Latin America. So it does help all parties, including the State Department, that want to legitimatize the election.