It could be that the parts were not normally supposed to be glued into the case but the person on the assembly line just went overboard with the glue gun on your particular unit.
The manufacturer would have no way of knowing this unless they disassembled it themselves or you had sent them pictures before going ahead and prying it apart.

Your decision to continue the dis assembly (without contacting the manufacturer again) after noticing the the excess glue absolves them of any liability for the damage in my opinion.