Not so at all. The person traveling slowly enough to break the otherwise smooth flow of traffic is creating a danger exponentially greater than the one created by a honking horn. If they're drunk or severely fatigued (as opposed to merely distracted) then the problem is even worse, and the need for corrective cues from surrounding drivers is even greater.
Contrary to what you say, the signal provided by the honking horn - while certainly negative - is actually pro-social and pro-safety, in that it's prompting an anti-social and dangerous actor to change his behavior.
Obviously, if this corrective behavior extends to aggressive tail-gating, screaming and yelling, brandishing firearms, or any other objectively dangerous act that makes the honker a part of the problem, then yes, they're both in the wrong. Once the honker's response escalates to actual rage, then he is - almost by definition - more dangerous than the trigger.
However, if the necessary negative feedback is provided with a reasonable measure of restraint (i.e. one that's likely to reduce, and not exacerbate the larger problem) then it's a good thing for everyone. Indeed, the willingness to assert yourself for the sake of safety in situations where others are distracted to the point of becoming general impediments is something that distinguished good drivers from bad.
And yes, promoting good flow is synonymous with promoting safety. There is an inverse relationship between the quality of flow and the likelihood of a collision.