You have to make generalities in life. When walking on a beach, you cannot check each grain of sand to make sure it won't hurt your feet. You remember that most sand in the past has not hurt your feet and that it is unlikely that this sand will hurt your feet, and you walk across it. Similarly, if you see a large group of nicely dressed people speaking quitely about a merger or IPO, you can assume they're businesspeople. You might be wrong - maybe they're all machinists fresh from the funeral of a friend that happened to leave them some money that they plan to invest.
No harm is done either way, and when presented with alternate evidence, the rational person will change their views to match the evidence they are presented with. If after hearing these people speak of the IPO and merger, the listener then hears them talk about having to go back to work on the metal lathe, drill press, and bar folder, he would then revise his beliefs to include some sort of metal fabrication industry for their employment.
So - please world - quit griping about generalities. They work just fine, and unless misused or abused, they are quite effective in helping us go about our lives.