There are many many different networks, none have anything to do with each other, and are run on their own (like different grocery stores have nothing to with each other, they just all sell groceries)
Network: each network has admins, the people who set the policies and rules. You can find their names on the website for the network, just use a search engine like www.google.com
to find it.
Servers: each network has servers that we use to connect to their network. Each one has admins who are responsible for seeing their server works and that the policies of the network are followed. Their names are usually on the MOTD (msg of the day, all the stuff you see scroll by when you connect to the server) The server admins are also responsible for seeing that their IRCops follow the server and network rules. The server admins answer to the network admins.
IRCops: ppl who "work" (no they arent paid, they are volunteers)for their server and keep it running and see that users follow the server and network rules. They answer to their server admin and the network admins.
Channels: each channel has a founder, the person who created it. They can then make other ppl ops, (@, operators). The founder decides what the channel rules are, and what they expect of their ops. The founder would answer to all the above if their channel was breaking network rules.The ops answer to the founder. They see that ppl follow their channel rules (as long as those rules arent against the network rules of course). Each channel has the right to say who can be in their channel. YOu cant see a list of the ops, but you can see who the founder is (depending on the network) by typing /chanserv info #channelnamehere.
Quite honestly, the network and servers admins, and the IRCops really arent going to get involved with someone being banned from a room unless the channel was breaking network rules. Kicking you because they didnt like your nick prolly isnt against any rule. Each channel has the right to say who can or cant be in their channel. You can also see the networks rules, policies and AUP (acceptable use policy) on their website. If there is no network policy against a channel kicking someone cause you dont like their nick, whether the admins agree with the op or not, they arent going to interfere.
To see how to set up your own channel, that is also on the networks website.