Armor

Curious about something. Why can't I change my personal armor to say, tactical body armor instead of a wimpy riot shield. I generally overpower my opponents, but am weaker in this category......even though I own more tactical armor than anything. How can I change this? my only option once I disarm myself is to choose the riot shield?

 

can only use drops, gifts and purchased weapons as personal armor.

 

thanks pal, that was a very insightful answer