There are things you can and cannot sell on eBay and they have pretty much spelled it all out for you. The rules and policies are all found in the Help pages and some in the user agreement too.
If you go to the Customer Support link at the top of any page and click on it and them type in "restricted items", it will bring up a link for restricted and prohibited items. If you are going to sell on eBay then it would be in your best interest to learn their rules first as you agreed to follow them and if you don't, you could have a very short selling career. As far as eBay not contacting you first, they don't and won't....mostly because you already agreed to follow their rules and accept the consequences, which are also spelled out, if you don't.
Sorry....but this is not eBay's fault and you can't blame them because you didn't take the time to read about what is or isn't allowed to be sold on eBay and that you got caught.