Unfortunately, the voting option gets abused way too easily, so that is why it is turned off.
The admin team is pretty good about keeping coverage throughout the day and night, especially on the MW2 server. There are several ways to reach an admin if there isn't one in game and the players would like a vote called to skip a map - teamspeak, the chatbox, pm. Many of us are usually around, even if there happens to be no admins in game at a particular time. Right now, there are 4 admins and a moderator logged into TS, and about the same amount active on the website, so one of us would have been able to respond rather quickly to your request.