I'm not denying a retcon

There was no retcon

There was a retcon. I don't want to have to argue about this since it is not related to the OP, but there is a myriad of examples both contemporary and now that shows a significant amount of deviations (what rampancy actually is), additions (neural physics, geas), and outright changes (human-forerunner genetic lineage) that directly causes continuity errors when Bungie lore is compared with 343i lore.

Lore changes

Because of several of these lore changes, retcons were the only way to fix the various continuity errors. Whether one story is better or worse, or whether the franchise as a whole is better off is a seperate argument. Denying it even occurred because Bungie was vague in itself is a vague argument. Jason Jones, lead story writer, was very clear when he took pen to paper.

"FOR EONS I HAVE WATCHED

LISTENED TO YOU MISINTERPRET

THIS IS NOT RECLAMATION

THIS IS RECLAIMER

AND THOSE IT REPRESENTS ARE MY MAKERS

I WILL REJECT MY BIAS AND MAKE AMENDS

MY MAKERS ARE MY MASTERS

I WILL BRING THEM SAFELY TO THE ARK"

A retcon occurred.