Actually, tubes are tremendously strong when end loaded and actually crush with much more effort than a similar square or other broken straight plane support. This is why we have round supports for bridges and the like. What I think you're trying to say is the tensile strength of a tube isn't as great as that of it's solid core variant. This would be correct. Just for argument sake though, if I had an M6 solid and an M12 hollow, the M12 would stretch less and fail with significantly greater force. That is unless it's walls were only as thick as tin foil.
