I totally agree. I have not played for a while and just went to get a scout rifle from the vanguard, and yep can't do anything with my materials.
I think they should have both options, which allows players to do it their way, as the info on Destiny originally stated.
For all the PVP lovers, you should be able to exchange crucible points for materials, that makes sense. But why take away the PVE players options completely, crazy.
Very demotivating Bungie, I hope this is an oversight, or you are setting up some kind of materials bartering system for later.