It depends on the level of scrutiny. It doesn't seem unreasonable. We review a lot more code per hour (usually C-like code though) but then we're not supposed to lock someone up for murder, we just find basic things like memory corruption. Don't even need to get into the business logic to find bugs that totally break the application, let alone all of it.

When writing Python (I don't have stats about reading), a 1.0 version of a small project took me 1.5 hours and consisted of 183 lines of code, so 2.2 lines per minute. That's much faster than this, but 183 lines is also a ton less complex than understanding the entirety of 180k lines and properly assessing whether it does exactly and only what it's supposed to.

10 lines per hour is probably taken as a lower bound to prove a point, especially because they argue about checking the whole thing (large parts can probably be skipped), but as a standalone statistic I would say it's probably within an order of magnitude from the true value. And for software time estimates that would be an amazing feat :p