I don't have experience on either Server Fault or Super User, but I believe your downvoted questions would be a poor fit for either:
- Is there a web-based platform for publishing & editing FAQs? This is a product recommendation question, which is generally not accepted on SF or SU (or SO), and was closed as "Not a real question" (not as Off Topic). Contrary to your statement that the comments didn't indicate anything being wrong, a moderator commented on this fact.
- How to choose a daemonized ed2k client. This is also a product recommendation question. There is one comment suggesting that it might be appropriate on Super User, but since product recommendations aren't considered constructive anywhere on the SE network, I'm don't think that comment spoke for everyone.
In other words, I think that your interpretation that your questions were closed and downvoted solely because users thought they would belong better on Super User was incorrect- I think they were downvoted and closed because they weren't appropriate for the SE network in general.