Because horn blasts are very specifically meant to communicate something to other ships. Once you're in "just blast it" mode you're seconds from disaster. I recognize the nobility of your suggestion, but I don't think it could have saved more than couple lives at most, probably none.
Well yeah, they were only minutes away at the point they lost power, there was very little time to do anything at all, that's why I asked. Personally I can't really imagine anyone holding it against them for using the 'signal that's for other ships' 'incorrectly' or 'against protocol' in such a situation. I think the comments speculating that the horn is either purely or in some way (e.g. solenoid) dependent on electricity is more likely the answer. I think a reasonable human in that situation who knows what's going on (that's why I mentioned that they apparently were able to radio/however they mayday that there's an issue) is going to do whatever they can, including use the horn wrong.
