The difficulty in this is defining exactly what qualifies as ban worthy material. Also, you may run into selective enforcement issues.The owner of Elite Trader can start by banning all racist content immediately.
The racist will be racist, regardless of whether they are allowed to post here or not.
Allowing them to post makes like a type of poll for us, based on the number of nicks posting racist material, and the frequency of the posts. This data gives some insight as to their current state of mind.
It also lets the world (of ET viewers) see just how ignorant racists are.
One of their goals is to rattle your cage. Like a baby loves a pacifier; they love doing that sort of shit. Don't give them the satisfaction:
If you can't make them look stupid with an educated response; Or,
If you can't make them look silly with a trollish response; Simply,
Ignore them.
They've likely had some childhood issues, and thrive on attention. So even just ignoring them has an effect.