I don't agree with this use of downvotes, but to answer your question, I suspect it is because you wrote that steel is non-stick. It isn't. Steel pans can be made non-stick with a coating of teflon or polymerized oils.
Not really. Just look for "carbon steel" in like, any internet search. Sometimes you end up with results that are Teflon coated, but in general carbon steel is the preferred term for pans used in professional kitchens because they're sturdy, relatively cheap, lighter than cast iron, and can be made non-stick through the same process used with cast iron.
Yes but carbon steel in this context refers to steels with moderate carbon content(under what you would find in cast iron) and no chromium that would make it stainless steel
Typical carbon steel alloy is about 1% carbon and rest iron, cast iron pans are >2.5% carbon and stainless steel has usually about 15% chromium and few percent of other metals aswell