What does Armchair idealist mean?

Armchair idealist meaning in Urban Dictionary

you will find three types of folks on earth: individuals who care, people who could not care less, and armchair idealists. Armchair idealists are the most inconvenient. They like to comment and criticise others' appalling behaviour however refrain from really going from their particular chairs and performing anything about any of it. This will generally apply to issues including the environment, globe comfort, starving kids, etc.