Now I think it *is* something for the administrators to look into that multiple tags can be excluded.
I did some research actually. The sticky is now closed, but I posted it there. No good answers. Bascially I wanted to know any game site, any at all that would have that feature. Excluding Steam. And even on Steam, this feature is so hidden, that I used Steam for years and did not even know it was possible.
The fact is, most game sites do not even have tags to begin with.
Maybe it is different for asset stores?
As for the reasons, the single tag exclusion was implemented rapidly after a feature request in community some 5-6 years ago. The fact that it was neither removed, nor implemented or expanded on the site as a documented feature instead of undocumented tells me something.
The calculation of actual usefullness, actual demand, accuracy and such vs. cost of implementing it in current framework is unfavorable. Or in other words, if it were cheap to implement, it would have been done.
Steam has a fixed pool of tags. And they are very accurate because of curators and or popular vote. So tag filtering is not only cheaper for Steam, but more usefull.
I researched this for a whole two minutes, so correct me if I am wrong.
Those items on those boorus are tagged by a dedicated enthusiast doing the tagging for many, many items and usually in an environment with a rather limited and standardized local flavor of the usual tags seen on similar boorus. Not only is the tag pool small, limited or not, the method of tagging is kinda by some formula.
The contrast on itch is this: there is like 100k persons tagging 10 items. Each with different views and opinions about word and tag meaning. And no guideline on the method how to categorize the item and putting importance on different aspects of the item. They just freely associate their item with tags and have perspective bias, because they created the item and also because they might select tags they think will make the item more popular, while an enthusiast would emphasize different aspects of the item.
I did not understand your first sentence, because I do not know to whom the "they"s referenced and what might not be done. If you were talking about steam, you can suggest tags for games. It reads "Popular user-defined tags for this product:" and shows a short list of tags you can expand to up to 20 tags where you can suggest tags yourself (from a fixed pool of tags).
Each booru does things its own way, but I can’t think of one with a small tag pool. Most are actually giant. IIRC Danbooru actually allows anyone to create a new tag, or edit the tags of other users’ posts. As of 6 years ago it had approximately 317,760 tags according to here.
There’s also volunteers who moderate tag misuse, but that’s much harder for video games than it is for single-frame images.
Now I’m not saying Itch should erase the tag limit or 100% become a booru, but if it already allows people to make up their own tags, then a higher limit and tag exclusion is basically expected.
Do they at least have guidelines how to tag? Because I believe that is a major issue on itch. There is no step-by-step checklist what to consider for a game. A concept in that direction is the prompt to select a genre from the available list of genres. If one fits, that should be selected as the main genre. If several fit, they can be selected as additional tags.
Also, you can tag different types of information. Like the content, theme, topic, stuff about the player character or lack thereof, features of the game, even things about the developer ("indie" comes to mind. While implicit on itch for all games, that is a popular tag on Steam), art style, general game mechanics, type of story, and so on. So which to chose from? If you ask many people, there will be a trend what seems to be catching about the game. If you ask one person for many games, a certain standard will emerge. But if you ask devs to tag their own games without some guidance, it will be hard to find games, even with tag browsing and exclusion.