It has been made very clear to us in the past two years that Cecil is not naive. Yes, at times, he borders on naivety, but I think it’s important to realize that Cecil is far from innocent. I don’t believe that you can grow up in a town like Night Vale and be innocent. So Cecil is very well aware of just what goes on outside of Night Vale, as Steve is, but he is also well aware of what goes on in Night Vale. He has seen just what happens to someone when you get too curious, or you know too much. He knows, because he’s seen it, he’s experienced it. Remember when he got called in for re-education in year one, in “History Week”? Why was that? Because he knew too much (about the Night Vale Elder Council). The very first day Carlos arrived in town, Cecil expressed fear for him and his team of scientists, because they were there for the sole purpose of getting to the bottom of the happenings in Night Vale. Cecil knows.
So when Steve began going off about his theories and the books he’s read and the things he knows the day he met Cecil at his wedding, of course Cecil reacted the way he did. Because I believe he wanted to protect not only his sister and Janice, but Steve as well.
Cecil knows he holds some degree of power in Night Vale. People listen to what he says, when he speaks. That’s why he is so fervent that angels aren’t real, despite the fact that he as seen them with his own eyes. Because he’s protecting his listeners by telling them what to do, what to see, and what to believe. So, by branding Steve a jerk? He made people believe that Steve is a jerk, and thus, by doing so, he ensured that no one else in Night Vale would listen to Steve, because no one else would like Steve, either. Because he knows that if people listen to Steve, eventually, something will happen to him, and maybe even his sister and Janice, too.
Cecil was trying to protect Steve Carlsberg. And he’s still doing it today.