There could easily be consent between co-workers. I know a few couples who met at work and ended up married. Even if one is a supervisor and one isn’t. There isn’t necessarily coercion — it really depends how much each of them actually needs the job, what other options they have(*), how much they care about “career.”
(*) – depending on circumstances, the supervisor could actually have fewer options than the subordinate.
Is dating at work always bad? No.
Should employers prohibit it, butting into private lives? No.
Should everyone respect consent? Yes.