tar someone with the same brush

To unfairly categorize someone or something as being the same as another person or thing, usually in a negative manner. Just because the CEO turned out to be a rotten scoundrel doesn't mean we should tar the entire company with the same brush. There is absolutely a segment of video game enthusiasts who create a hostile and toxic environment online, but tarring all gamers with the same brush does a disservice to the community.

If you tar someone with the same brush you wrongly believe that they have the same bad qualities as others in a group of people they are connected with. I am a football supporter and I often have to explain that I'm not one of the hooligan sort, because we all get tarred with the same brush. In the loans business, the better operators get tarred with the same brush as the less scrupulous ones. Note: You can also say that someone is tarred with the brush of something. Why should all English people be tarred with the brush of football hooliganism? Note: This expression comes from the use of tar to mark all the sheep in one flock to distinguish them from another flock.