Why?
First, I think that after not that long on the game you get used to the scripts. People see someone acting a PDS script and they accept people's statement that it's PDS. If the only thing a script generates is 'you want to hurt Person X right now', though, now there's an RP uncertainty if someone claims 'PDS made them do it.'
Second, the scripts often are immersion-breaking in the context of RP. They range from 'making no sense in the scene' to 'referring to things that don't match the description of the room at all.'
Ultimately, almost everywhere we have policies about how people should act, including prompts from the code, and enforce it with XHELP. It seems like a relic of an earlier time that we don't do this with PDS. We should be telling people how to feel and act and expecting them to RP accordingly, so that PDS feels like a natural part of the world and not a jarring intrusion into it.