there simply is no definitive list of words
I agree. In Amateur Radio we faced this problem in the UK in the mid-90s on the ax25/tcpip network when the Home Office made the sysops responsible for content. Filtering messages off for human reading if any words on the "list" occured was the only practical solution. The sysops gradually built up a "list" and circulated it. The rules state something like the sysop must "take all reasonable precautions" to prevent offensive material circulating. So a sysop filtering/human reading is OK if an offensive message got through, whereas one not doing anything lost their licence.
This still leaves the problem of the English-only speaking sysop getting smtp/nntp in a different language!
Regards
Chris
PS Sorry about this being OT, my one and only post on this topic.