Doesn't intent matter? I cannot control the entirety of society with my will, nor can I control what animals I unknowingly kill, but I can react to the things I know with my own actions.

It also seems irrational to let the "better be the enemy of the good". There is no rule that says that unless I solve all the problems at once, solving one problem is being hypocritical. The single decision doesn't get irrational just because I am not actually making 100% rational decisions all the time. That would only be hypocritical if I claimed that all my decisions are 100% rational when they are not.