I think that merging demo and S2 servers on the list was a terrible idea personally. It's pretty hard to see what's going on in S2 with so many demo servers crowding the list. S2 hosts with a single-digit number of connections(pretty much anyone but cargame, TC and a couple drift servers...?) can get bumped pretty far on the server list, making it very hard for them to grow. It's not bringing anything for S2 users, and not even a good S2 advert for the demo players, as it shows there is actually much more activity on demo.
Of course you can filter out demo cars as Whiskey said, but you're blocking all the S2 hosts using demo cars(more than you think), so this is not a practical solution.