If the supply of government bonds is reduced, most of the money that would’ve gone into gov bonds will go into other investments (because if you want to, e.g., save for retirement, the unavailability of gov bonds is not going to stop you from finding some way to save for retirement). Investment has a different effect on the economy than consumption (e.g., choosing to have a kid) does, and your policy proposal replaces consumption with (private) investment.
If the supply of government bonds is reduced, most of the money that would’ve gone into gov bonds will go into other investments (because if you want to, e.g., save for retirement, the unavailability of gov bonds is not going to stop you from finding some way to save for retirement). Investment has a different effect on the economy than consumption (e.g., choosing to have a kid) does, and your policy proposal replaces consumption with (private) investment.