As a recently returned sec main, I've noticed this too, but I've also noticed that when I tried to step up and actually do the job as security, the rest of security jumped on me about it and refused to cooperate. Specifically in the round that just happened - I wanted to start tagging people for misuse of comms and disobeying orders to stop discussing certain topics on comms, and for heckling a team of heavily armed skrellians that we were trying to peacefully resolve issues with, and the rest of security kept shutting me down anytime I brought it up.
There seems to be a common mentality among security to just not do anything unless they're antags.