It means that one of your decisions places more weight on one sub-aspect of future outcomes (the suffering and injustice your progeny might have experienced or created) more than other aspects (the suffering and injustice your progeny might have directly or indirectly prevented) which third parties might see as equally important. If these decisions reflect your actual values then they aren't foolish or cretinous... but I'm not sure I understand your actual values. Is there a consequentialist argument by which potential future worlds which include your descendants would be inferior to worlds where that space is filled up by the marginal additional offspring of others instead? Is there a deontological ethic which you should follow but others shouldn't, or one which everyone should follow in which "we should undergo voluntary self-extinction" is the correct ethical result?