In general, how would you respond if a girl mentions that she's talking to/interested in another guy?

Happened in my case today. I was texting a girl from Tinder, and told her I'd call her when I was free later in the afternoon. She responded, "Well I have another boy from tinder calling me 30 minutes before you so... :P I have work, so I can't" I was kind of in a bad mood and not looking to compete with another guy for some tinder girl's attention, so I told her, "That's cute, you have fun with that". She immediately told me it was a joke.

Was my response the right move in this kind of situation? I kind of feel like I came across as too passive-aggressive/acting like a little bitch. Would like to know, so I'll know what to do in the future if this happens.