Help vs Hurt

"There will be a day when you will wish that you had done a little evil to do a greater good."
--Sybilla (Kingdom of Heaven)

Federal welfare programs are sometimes justified using some variation of the following: Yes, the programs are subject to abuse. But even if just a few are helped, then the programs are worth it.

Why is this argument any more valid than one that focuses on those hurt by these programs? For example: Yes, the programs help some people. But even if just a few are hurt, then the programs are not worth it.

All government programs that provide resources to some require that those resources must be forcibly taken from others.

Is not aggression on anyone for any purpose...bad?