TARFU: Whether they believe their posts or not, trolling is still trolling.
So that's what your vast knowledge of the internet has taught you...
Trolling is specifically posting to provoke reactions. If, for example, you post saying that the earth is flat and then laugh at the chaos that ensues, that is trolling. If on the other hand you post that the earth is flat because you actually believe that the earth is flat, and don't care about what posts the others make, that is not trolling. And depending on what the post says (Hey everyone, let's set fire to government buildings!), treating said post as a troll post may be ill advised.
TARFU: but unless you start banning by IP number
Why do people assume that the IP number is static? There are currently ~4.2 billion IPv4 addresses, and way more people than that. Add to it the IP ranges that are assigned for specific functions (10.0.0.x, 192.168.x.x), and a single IP address may be used by multiple people, and most people also use multiple IP addresses. Until IPv6 is properly used, assuming that IP banning actually does something is almost on the same level as assuming every post is a troll post.
But what do I know, I'm just a person on the internet, thus most likely trolling.
Edit: Forgot to say, thank you for your answer.