I was racing in one of the demo servers last night. There's only one server full of people racing in Blackwood Rallycross Reverse. The thing is I saw a lot of people cutting the first chichane in a way that they can just dive right into the first dirt part of the track at high speed. I asked them kindly not to cut that chichane so badly and people can dare to ask me to "stfu". Am I wrong here?

They are demo racers, they don't care. When i was on STCC Bronze, the corner cutting you can't do due to barriers on the gravel.(Autocross objects)

Sadly the only way around this is to get on a licensed server, where people have a reputation to uphold and autocross objects can be used, just as Dalek said. On the CTRA servers you can also get penalised for cutting.
To answer your question, madbikes, you weren't wrong - they were, but as said before, there's hardly anything you can do about it in the demo

Thanks