Chris has always believed that dating is a step-by-step levelling up process. You start as acquaintances, then become friends, then move on to dating, then become sweethearts. Chris spent weeks talking to Catie before their first date. By this time he had become smitten with her and assumed they'd be together forever, but (I'm guessing) this is only because Catherine didn't put any roadblocks in the way, for the sake of the trolling experiment. In a normal situation, a woman would have sent out signals to get Chris to back off from his marriage fantasies. Catie was "nice" to Chris, but this doesn't mean she was willing to say anything that would have caused Chris to get discouraged. I'm sure he put out feelers every step of the way, and saw nothing but green lights. Catie never said "I love you" like Julie did, but she never said, "You're moving too fast, you need to back off." At least, not until Applebees had been accomplished. Chris made assumptions he had no evidence for, but a normal woman would have corrected him very quickly. Catherine was deliberately trying to be nice and polite to Chris, to contrast Jackie and Kacey, but the drawback to this was that Chris thought she was a sure thing. So the 97% on OKCupid was only a first step. Then Chris had to go through his checklist to get to the bonus round, and from his perspective this was going as planned.
This is speculative, but I'm pretty sure this is what the Catherine emails and texts will reveal, based on what we've already seen. Maybe he was pushy at the bowling outing, but I want to see the earlier correspondence for context.