You're a scrub. It only shows to people of certain skill level, which bungie decided.
If you're good you'll see it, like me. If you're bad and have no skill you won't see a weapon slot at xûr.
-
Uh...y-yeah, I knew that. Good thing I uh...I could s-see it. Just bought 4...b-because I'm not a s-scrub... ...r-right guys?