I think it would work better if the games were rated and if you didn't want them to be, you switch it to unrated. People might not always realise you have to change it to make it rated? It feels more meaningful when the games are rated!
I'm assuming you are joining tables from the Tables tab. That is not the intended way to join games with strangers. If you want to play rated games, you can use the Automatch tab, where you can choose what kind of games you want to play and set the options so that you are only getting in rataed games.
Thanks. Yes I always join from the Tables section - I've never managed to find a game with a stranger through the Matching tab...
If you can post a screenshot of your automatch tab, maybe I can see why you don't get paired.