What is Armchair Idealist?
1.
There are three types of people in the world: people who care, people who couldn't care less, and armchair idealists. Armchair idealists are by far the most annoying. These people love to comment and criticise others' appalling behaviour yet refrain from actually moving from their seats and doing something about it. This can commonly apply to issues such as the environment, world peace, starving children, etc.
Armchair idealist, carrying plastic bags in each hand: "You should always use reusable shopping bags!"
See