There is only two ways you can loose sec status
A) Ganking in high sec
B) Piracy in low sec.
Pvp in the forms of…
Null Sec Engagements of any kind
Wartarget engagements (including faction warfare).
…Does not impact sec status.
Sec Status is gained by killing NPC Pirates, known as “rats”. The bigger the rat, the greater the gain. I.e. you do not only get bounty payments but also sec status gain.
So… if all a player does is PVE and maybe PVP in null sec (which is exactly the sov null playsytle) they skyrocket to 5.0 sec status
Same goes with high sec carebears that refuse to pvp in low sec for example.