The use of the term “do-gooder” as a criticism or derogatory label implies that doing good can be bad. That is an intriguing concept. I guess the appearance of doing good can actually be a sham, an attempt to pass some evil off as doing a good thing. Or maybe an attempt at doing good could have unintended negative consequences which are worse than the attempted good. Then perhaps someone desires to self promote by doing something good but their selfish motive makes the effort meaningless or at least greatly diminished.
I suspect that any of us could find examples of these ways, in our opinion, doing good has been questionable. In politics we probably noted that a proposed good is actually detrimental to the majority. In the religious context of Christianity and the Bible we see Jesus and Paul both casting doubt on supposed efforts to do good by raising the issue of motivation. Are the good actors seeking to self promote, self justify? If so, the Bible leaves plenty of room to wonder about the overall efficacy, both for the supposedly benevolent and their benefactors.
True righteousness is a matter of conscience, not fear of retribution or desire for acclaim and self promotion. A great deal that Christianity passes off as righteous is actually detrimental to the spiritual well being of its adherents. And in the process of misrepresenting true righteousness they sear the consciences of its membership and destroy any prospect of the covenant of peace being a reality in our lives.