Google's return policy is 15 days. You're talking 2 months! Consider yourself lucky that they're even willing to give you an exchange, regardless of how they're doing it. Normally you'd have to get warranty service done by Asus (arranged through Google) after this much time has passed, and be without your N7 for a few weeks. Jason probably laughed in amazement (or frustration) that you actually expected a free replacement, not repair service, 45 days after the end of the return window. He probably should have waited to laugh until after hanging up with you, but I can understand his reaction.
Read the policy:
http://support.google.com/googleplay/?hl=en#/answer/2411741
Replacements:
Within 15 days of delivery, if you happen to receive a defective device that you'd like to exchange for a functioning device, please email our support team. We'll work with you on next steps or connect you directly to our partners for replacement options.
Regular warranty service and out of warranty repairs:
After 15 days from delivery or for an out of warranty repair, please review warranty information for your device.
Nexus 7 limited warranty:
The Nexus 7 is manufactured by ASUSTeK Computer Inc. ASUS provides a limited 12 month warranty for the Nexus 7. Please refer to the warranty card in the Nexus 7 packaging or review ASUS' limited warranty details.
If your Nexus 7 was purchased from Google Play, please contact Google customer support for service on the ASUS limited 12 month warranty.
If your Nexus 7 wasn't purchased from Google Play or you're looking for out of warranty repair service, please contact ASUS directly.