I think it's a rebuttal against claims that LLMs are incompatible with large code bases. It's not so much a flex about the quality of the code, it's more a flex about the complexity of the code and the LLMs ability to deal with such complexity.

Whether or not that complexity is warranted is a different story.

The codebase may be bloated by a factor of 10 but if the costs associated with that are less than the costs of developing the software from a business standpoint the choice is clear.