You can remove them in an exactly same way as any other shortcut – with bind -r
for i in "-" ; do bind -r "\e$i"; done
If you hate loops, you may do it manually:
bind -r '\e-' bind -r '\e0' bind -r '\e1' bind -r '\e2' bind -r '\e3' bind -r '\e4' bind -r '\e5' bind -r '\e6' bind -r '\e7' bind -r '\e8' bind -r '\e9'
If you do not want this modifiers not only in Bash sessions but everywhere where GNU Readline provides them, add the following lines not in your .bashrc
but in your .inputrc
:
"\e-" "\e0" "\e1" "\e2" "\e3" "\e4" "\e5" "\e6" "\e7" "\e8" "\e9"
(Yes, just list them).