I still find myself saying committed suicide. 'Committed' doesn't seem overly negative to me. Its more the suicide word that is the bummer in that phrase!..I think you can commit to a relationship, commit to studying, commit your time to volunteering to feed the homeless etc etc, So yeah its just a verb to me neither positive or negative. If someone doesn't like it then Id try not to use it around them, but I think we probablly all have bigger issues than semantics if we're on this site, sadly.