Brandon Hawking has written his thoughts about i2p on the forum - https://forum.cryptonote.org/viewtopic.php?f=2&t=205#p670
This has been discussed at length, it's to ensure that (generally speaking) an attacker can't determine if you are using Monero or not.
We're not beholden to what the CryptoNote academics believe, so whilst any input they have to offer is always appreciated, we've already diverged far from their reference code, and will continue to do so as we fix deficiencies in their protocol (some of which were highlighted in the Monero whitepaper review).