Define intelligent thought. Just because a map doesn't have a design like one of valve's maps doesn't mean it has no intelligent thought. It might not have the same mindset as valve's maps, but it's directed towards a different kind of gameplay.
You want strategy in maps. A plan, to do this and this, and then you have to do this with this character to get over here, but this character is not as good at this point, and this character is better. You aren't going to find that kind of logic in surf/mario_kart. Does it make them bad? I don't think so. Maybe you do. Maybe we should agree to disagree.
I can understand how you could feel that surf/mario_kart maps take the game away from what it was originally designed around, strategic classes and maps, but I think it's awesome that the game is so open that people can design maps like surf/mario_kart that bring a new feeling and mood to the game. Players get bored of games that can't bring something new every now and then, and games die when players get bored of it. Look at Unreal Tournament. The basic game is alright. But throw in all the mods and mutators, and you have hours and hours of fun you can have trying out all the different stuff. The ability to generate new experiences in the game gives the game many more years of life.
That is why I feel people should accept surf/mario_kart maps as a necessary evil. You might not like them, but the game would be at a loss without them. How much of a loss is negotiable. But take it from me, a casual player, once I get bored with something, I rarely come back to it. I got bored with tf2 around the time of the first achievements coming out. A handful of maps that are just played over and over again. Certain classes being way overpowered (imho), and I wasn't going to wait around for things to change. I found surf maps, which lead me to Mario_Kart maps. I didn't have to worry about overpowered classes because everyone was overpowered (shotguns one-hit-killed, spy could cloak for a minute or two, medic could overheal someone and make them almost unkillable. None of that stuff mattered, because I was having fun again. Now look at me, I want to make a map, and give back to the game. And none of that would had been possible if I hadn't had found the surf/mario_kart maps.
It's a necessary evil, deal with it.
edit: No...better, go play them, and have fun.