An unloaded gun is just a crappy hammer
The question wasn't an unloaded gun, it was an unloaded chamber, with the implication of a loaded magazine in place.
I guess your definition of loaded is different than mine, I consider a gun unloaded when anything short of disengaging any safeties and pressing the trigger doesn't result in a bang no matter how manny rounds are "in" the gun.
The two loudest noises in the universe are a "click" when you expect a "bang" and a "bang" when you expect a "click".
I understood what you ment. If there is not a round in the chamber the gun is unloaded. There is no legitimate reason to carry a modern simi automatic pistol without a round in the chamber.
ETA: I saw that there is a similar discussion of the definition of "loaded" after I posted this.
IDPA, USPSA, IPSC, NROI, NRA, ATA, NSSA, and IMG all consider a firearm to be loaded if there is a round in the/a chamber, (inserted) magazine, (inserted) clip, or cylinder.
State laws vary, but most (but not all) states that define "loaded" have a similar definition to that above. For states that do not define "loaded", most instructors and references (such as Handgun Law US) recommend using a similar definition to what is stated above.
A hammer (rock, brick, etc.) cannot possibly be a fully functioning firearm in fractions of a second. So if your understanding is that a semi-automatic pistol with a loaded magazine in place without a round is the chamber is a hammer (crappy or not), rock, brick etc. one or more of the following applies to you [1] you heard someone say this and thought it was cute to repeat - but didn't think it through very well, [2] don't know too much about guns, [3] you don't know too much about laws that apply to guns, [4] you don't know much about using guns for defense, [5] you don't know too much about using guns for organized competition and/or [6] simple logic is slightly out of your grasp.
As an example: Person "A" is facing an aggressor at 20 paces and has a gun with a loaded magazine in place without a round in the chamber - and person "B" is facing an aggressor at 20 paces with a cheap 22 oz plastic and metal hammer - and you have a choice to be person "A" or person "B" - which one are you going to choose?
I think most people here would pick "A", and further, most people here would think that actually choosing "B" would be pretty stupid.
And while it is certainly not my preference to carry a firearm (for defensive purposes) without a round in the chamber, there are valid reasons - for some people, in some circumstances - to carry in this manner; and is much better than carrying a hammer, rock or brick in most defensive circumstances.