The problem is that some time, the person robbed might not be able to afford to replace their bike, which may have been their only way to get to work and other places they need to go... which doesn't leave them much of a life. It's easy to blithely say "oh the {item stolen} isn't important," but it might be to the person losing it. It's not only people who can "afford" to lose their belongings who get robbed.