Don't start up with me or else ... (Shabbos 17a)

Hillel asked Shamai a perfectly innocent question - if you made a gezeira on the juices of grapes being machshir even when they came out on their own then why weren't you also gozeir on olives? In the gemara Shamai doesn't even respond to the question but just says, "Don't bother me about olives or else I'll be gozeir on those also." Tosafos explains why the gezeira was made only on grapes but not on olives but it doesn't explain Shamai's response. Would he really make a gezeira just because Hillel was questioning his intial gezeira? Is that how the Rabonnon work?

The Chasam Sofer explains that Shamai was saying to Hillel that he didn't feel that a gezeira was necessary on olives for the reasons that Tosafos enumerates. However, if Hillel really was concerned that people wouldn't understand the distinction between olives and grapes then Shamai said he'd be forced to make the gezeira on olives also so people don't get confused. It wasn't meant as a threat just that if Hillel really was confused about it then it showed that there was a need for the gezeira on olives also.