This is one of my pet peeves. This is a professional setting and the employees are not 13. They should be mature enough to be able to handle their personal lives without bans or frown upons. Someone can't handle rejection? Who says he/she can handle criticism? What about disagreements?
To me this is a personality problem that should be dealt with accordingly. Company-wide bans or silent rules can hide bigger problems.
Recently, however, the smart ones have been shouting back "British or European?"
Thanks for tall children...
On the other hand, there are plenty of people who can be in a relationship while working with each other. Hard cases make for bad law, and I'm uncomfortable with blanket proclamations against relationships at work, as long as two people at different levels along the same management line aren't seeing each other.
If the company is seen to have encouraged or even acknowledged the relationship it can create a huge liability, especially if one of the people involves feels like they got stiffed because of relationship issues (sidelined, transferred, had to resign, etc).
The number of couples who say they met at work suggests that blind eyes are often turned, but a company has those official bans on intra-office dating for good reason.
If, for the reasons you describe, they wish to maintain a public position of "we not encourage dating coworkers" that's one thing, so long as they don't actually think they have any say in this matter.
Shame that companies believe that just fine. They can and will fire an employee if "no dating coworkers" is a policy that said employee violated. You are welcome to avoid working for these companies, but that's your only recourse unless you have an overwhelmingly string case that discrimination was involved.
As a manager, you should be prepared for this eventuality once you become aware of the activity. It is unreasonable to forbid all dating since many happy marriages were established between people who met in the workplace. It is reasonable to let people know that they may face dismissal if their dating issues enter the workplace and prove a distraction for themselves or others.
On a practical level managers wish to avoid unnecessary turnover or drama in the workplace. Knowing that employee dating will almost inevitably lead to one or both of these things, I understand the "frown upon" aspect. The employees themselves should be adult enough to know that they are gambling with their jobs.