Those do-gooders who talk about ideals without understanding the reality often end up doing more harm than good.

do-gooders 是由动词短语 do good（做好事）加上后缀 -er 构成的名词，字面意思是"做好事的人"。这个词常带有轻微贬义，暗指那些自以为是、不考虑实际效果就想帮助别人的人。