first of all there is neutral gear in the game.. its every peice of gear including drops, crafted, pvp, commendation, operation, flashpoint sets etc. and the top end stuff isnt going to be better or worse than the light/dark stuff.
Secondly as far as relics go you may be correct but complaining that the Auction house doesnt have any , neutral relics doesnt mean much. the game is 9-14 days old.
Thirdly staying strictly neutral isnt playing your way either.
I play my BH as i feel the situation dictates, and im light 3 now (with almost 3,000 dark points) against me.
Playing neutral by picking choices you dont want to make is just as artificial as someone picking all dark or light.
Lastly ,OP, you stated your self that the matrix relics are available to you. so go get those.