I don’t know about your field, but that does seem somewhat suspicious to me. I suppose it depends on which company, which product, and which field.
For instance, I could presumably see an argument for turning down a salesperson applicant to Microsoft for not having used Microsoft Office before. ie, if not using a given product demonstrates lack of experience in the field.
Is the product well-known or a standard in the field?
Nobody here seems to have read the article, so to clear things up: Onerep’s CEO is the one running the people-search networks. Mozilla’s CEO was not. (As far as we know.)
Mozilla dropping Onerep is a good thing. It shows that they respect user privacy.