Agree. In Europe, if you follow the recommended safety distance, you always have the time to brake if anything happens to the car in front of you. The problem is that people do not follow them.
If you leave a large enough gap with the car in front, then people will merge into that gap. If you then slow down to create a new gap - people will overtake and merge in again. You end up travelling slower than the rest of traffic, with people overtaking and merging, which creates dangers in itself.