Brown is getting paid to do a job. If you were low man on the totem pole at some company and your only job was to make spreadsheets and you just didn't do it, do you think the people in your group and/or your boss would say OH HEY GIVE HIM A BREAK. HE'S TRYING REAL HARD. People out to get ridiculed for jobs they are being paid to do but failing to perform.
NFL players should catch open first downs and touchdowns. Nobody is asking him to replace KB. People want him to make routine catches with his hands and keep the ball away from his body. People want him to play like a professional football player.