Literally "To put everybody in the same sack". This is what you say when you criticize a group of people and you make no distinctions. Imagine you had a staff meeting at 8:00 am and only two staff arrived late at the meeting. You got really angry and criticised the entire staff. And obviously someone was bound to say: "No pongas a todo el mundo en el mismo saco." Another typical example is when people criticize civil sevants or plumbers. What about an English equivalent?