Consultants' reputations and where do they come from?

I've had some very interesting conversations concerning the reputation of consultants and especially HR consultants. I still don't have a definite answer to why some of my professional areas have this negativity embedded in them, but I have some observations and opinions on this matter.

One important factor might be a cultural one. The majority of my student friends in the Helsinki University of Technology have specialized in some technical area: testing, mobile platform design, high speed computing, etc. My opinion is that technical experts are more familiar in dealing with concrete, formal and absolute definitions, which are more present in natural sciences. For example it is quite easy to differentiate Java and C programming languages or Windows and Unix operating systems. In many of the HR-areas, things are not so simple or well defined. Okay, I admit that payroll, work hour- and vacation-plannings are somewhat straightforward, but there are others too. How about knowledge? Or talent? Or even better yet, intellectual capital? Even though these don't have such precise definitions, they are still present in every organization. It doesn't make the value of knowledge/competence/talent any less significant if it has many names.

Other thing might be that consultants are quite often present when something is changing in the organization. New work distribution, org charts, allocation of resources... All of these tend to have more negativity accompanied and since consultants are somehow involved in the changes, it is easy to project the negativity into them. By accident or on purpose. I cannot deny that the consultant herself (or himself) might have an effect on his/her reputation. Really poor skills and lack of expertise is impossible to conceal, but proving one's worth is an uphill battle for consultants.

I don't have anything against technical areas, but my experience is that technical experts' attitudes are more hostile towards consultants and HR, than towards accounting for example. Maybe it's a cultural thing, maybe the negativity comes from some unfortunate events. Generally speaking, people should respect and appreciate others' expertise, no matter what the area is.

I try to keep in mind that the consultants are never "uninvited". Their presence in a change process or as a part of an organization, is justified and approved by the organization itself. The approving level might just be a higher one.