That's what I never got about Suder, if he was a full telepath, first he would have been impressively valuable to the mission and second he would have laughed at the Vulcan's touch-telepathy-information-dump when he should have been capable of a much more "selective" inspection of his crewmates memories...
I assumed Suder was a gimp.
Something had deprived the poor bastard of his telepathy which is what created his antisocial, homicidal and terroristical behaviour.
I've watched enough Criminal Minds to figure out that telepathic dysfunction can easily be substituted for Sexual Dysfunction, and all the murderous extents these people are willing to go to replicate the "highs" from a healthy sexlife they're incapable of doing so vanillaly.
Maybe Suder did something wrong on Betazed and he was lobotomized?
Suder's defence "i didn't like the way that guy was looking at me" for murder is a much more intense defenceif he had also included the conditioner "I didn't like what he was thinking while he was looking at me"