Expected Behavior
While most other entities can be placed using a dispenser such as TNT, or Minecarts. When powering a dispenser with an armor stand in the inventory, the expected behavior is for it to be placed.

Current Behavior
The dispenser ejects the armor stand. This is inconsistent with dispensing other entities.

Since mobs can be placed and equipped using a dispenser, I would expect that dispensing an equipping and armor stand to make sense.