Got the answer. He says he deleted the stuff on purpose on steam, also deleted on his PC so couldn't even reupload it, but he doesn't want to anyway. And yeah, he's still mad at the LOTUS team, I'd not translate what he wrote.
Unbelievable... For card manufacturers just extremely stupid! 
I wrote to him. Hopefully he will upload his content again.
The fact that he no longer builds something new is one thing, but that he deleted finished objects from steam is not ok
Wie es scheint wurden deine Splines gelöscht...warum? Ich denke, dass nicht wenige diese Splines verbaut haben...
Kannst du diese Splines bitte wieder hochladen?
Generell würde ich alle bitten, die etwas in den Workshop hochladen, dies auch dort zu lassen. Denn es gibt immer irgendjemanden, der diese Inhalte verbaut. Es ist einfach extrem deprimierend, wenn man den Editor öffnet und Objekte fehlen und man diese Bereiche dann alle nochmal neu bauen kann - so macht das keinen Spaß! Also bitte seid hier solidarisch...
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It seems your splines have been deleted...why? I believe quite a few people have used these splines...
Can you please put those splines back up?
In general I would ask everyone who uploads something to the workshop to leave it there. Because there is always somebody who uses this content. It's just extremely depressing when you open the editor and objects are missing and you can rebuild all these areas again - so it's no fun! So please be solidary here...
If you feel that way, you don't have to buy the game. The LOTUS simulator becomes a very complex and realistic simulator.
Copied from the home page:
"Hardware interface
LOTUS is able to handle the most different input devices - from keyboard and mouse up to game controller, pedals or steering wheel. But if all this is still not enough, one can plug in its self-made driver's desk and control it with original component parts."
So I think an interface is planned by the developers. Wait out!
