It is possible to upload torrents for other trackers on Gay-Torrents.net, but these are rather the exception.

Indeed. But that is a privilege now accorded to a very few trusted members only. Personally, I find open/public tracker sites so insecure and dangerous, I will never download torrents using public trackers, wherever they are posted.

Open/public trackers do not use the passkey system, you do not need to be a member to access their torrents. This distinction between public/private may seem unimportant, but it is important in regulating who has access to what the members provide.

Back to the question, the trackers operate differently. What is also important is how many members each site has, how many are seeding torrents in question, and how many are leeching. One way of increasing an uploader's stats is simple - his torrent needs more leechers. Many people are members at all four sites I have mentioned, and, apart from differences in banned content lists, people often have access to the same torrent at any of the four sites. So, many people will download from the site they prefer, where there is a choice.

Something else could be the issue, but this seems like the most likely explanation.

To get higher ratio it is always the best to post stuff, I am sure you have something that is not here already.