I agree with your larger point. Though I think it's pretty natural to wonder how the poster ended up with a multi million line codebase.

2M lines of code is 15 people committing ~26k lines of code per year (~100 lines per working day) for 5 years.

15 people is a pretty small startup, what if this is a 50-person startup?

Doesn't seem like that much to me, depending on what you're building and the size of your team.