Our Help Center contains the following guidance:
You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page.
Asking, "Is it ethical?" is not a workplace issue, it is a personal decision issue. A problem related to the workplace would be something like:
Company policy states that "Company resources should only be used for work-related duties. The internet should not be used to write personal blog posts, browse Facebook, etc." That policy is not strictly enforced (management turns a blind eye to people who check their personal e-mail at work, or check Facebook during lunch for instance). Getting answers on Stack Overflow seems to be in line with the policy, but I am unsure whether answering question applies.
Personally I believe answering questions benefits my employer because it improves my understanding of the skills required for my job, and improves my communication and problem-solving skills.
I don't want to put my manager in a difficult position. If I ask, the policy may indicate that he has to say no to be in line with the policy, while in practice he seems to be willing to turn a blind eye. Is this a situation where the expression "It is easier to ask for forgiveness than permission" applies?
The problem is clear: you don't want to put your manager in a tough situation. The question is clear: is this a good occasion to keep your mouth shut and apologize if it becomes an issue?
The issue with your question as-asked is it is asking us to make a judgment on what is acceptable while entirely ignoring company policy which is what would cause the problem in the first place. You are essentially asking us, "If you were the boss, would you allow people to use SO during work hours?" which is a hypothetical question that will only solicit discussion -- not practical answers that will help future visitors.
Your question got popular because a lot of members of the Stack Exchange network browse from work (likely in violation of their company policies), and want to feel justified in what they're doing. That unfortunately gave you the wrong signal in what is appropriate for the site, and made it harder to properly edit and put on-topic.
In situations like this, I would recommend not trying to edit your question (because of the existing votes and answers that would be dramatically impacted), but rather than ask a separate question that focuses on asking "practical, answerable questions based on actual problems that you face" assuming that you actually do have a problem, and that the current question didn't give you an answer you could apply to that problem.