You are very wrong there. All employees must have a SIDA clearance. You have a limited SIDA clearance that grants you access to limited areas on the airport including lounges and the ramp in the vicinity of your aircraft. What most airlines don't do is badge you for full SIDA clearance including escort privileges and unlimited ramp access. No badge is required for the basic clearance. Your employer ID is sufficient.
I am surprised however we are even having this discussion. How hard is it just to follow the rules. Are we in kindergarten or something?