I don't find it derogatory per se, but also don't think it's necessary to discuss "bench researchers". If anything, I think most people tend to have a bit of in-group bias, such that only a computational person would think "bench researcher" is derogatory, and only a bench person would think "computational researcher" is derogatory. The most plausible way you would offend would be if someone got the impression that you had a negative or patronizing view of bench science or bench scientists (see for example https://xkcd.com/793/ for an example of how this attitude can be expressed).
However, there isn't any neat division between roles in a biological laboratory; saying you want to work with "bench researchers" could imply that you don't realize that people who do wet biology may also have computational skills, and that those skills may be comparable to yours (or, likely, far superior if you haven't had computational experience in their specific domain).
I think it would be sufficient to make clear that you are interested in working alongside bench research (rather than researchers). However, if you are writing a cover letter for a job application, I think you can be a lot more specific to the role you're applying for and express specific interest in the technologies used in that lab; you can read papers published by the members of the lab to get an idea of what they do. That may be more difficult if you haven't had any exposure to research methods in biology, but you're going to be a better candidate if you can learn what you can ahead of time. Otherwise, your application may seem out of place.
The categorization of research depends a lot on your perspective. "Clinical" research, though refers to work done in human subjects for medical purposes, such as trials of drugs or devices; for a clinician/physician, the antonym would be usually be "basic research" referring to studying of the underlying processes or mechanisms; basic research can include both theoretical/computational approaches and wet biology/bench science. Clinical research can also involve primarily computational/statistical approaches, though, especially in fields such as epidemiology and public health.
Because these lines are not drawn neatly, I'd advise against using the terms without feeling comfortable with them. Instead, say what you really mean, plainly and specifically.