It doesn't make much sense and is inconsistent to require a pickaxe to mine a lantern and obtain the item when you can break the block on which they are mounted and them drop normally.
Possibly intended.
Related to MC-203623.
Comments 9
But lanterns are included in MC-173833 (Which has a Mojang Priority)
True, but that doesn't mean they will change it for all the items listed in MC-173833, or that they will fix it at all (or any time in the near future).
However, I have suggested that they add rails to the MC-173833 list.
Also MC-170900 had a Mojang Priority and was resolved as intended so it can happen
As lanterns are made of iron, they should require a pickaxe to be mined. If this bug is going to be fixed, they should make lanterns not drop when their support block is broken instead of making them not require a pickaxe to be mined.