5k likes of code a day is 10 lines of code a minute solidly for 8 hours straight. Whatever way you cut that with white space, bracket alignment, that’s a pretty serious amount of code to chunk out.
If I am writing Go, it is easy to generate enough if/else and error checks. When working in java, basic code can bloat to big LoC over several hours(first draft, which is obviously cleaned up later before going to PR). React and other FE frameworks also tend to require huge LoC count(mostly boilerplate and auto completed rather than thoughtfully planned and written). It is not that serious amount as you may think.
Nitpicking like this must be fair, if you look at typical AI code - styles, extra newlines, comments, tests/fixtures, etc. it is the same. And again LoC isn't a good measurement in the first place.
Not all my 5k lines are hand-written or even more than a character; a line can be a closing bracket etc. which autocomplete has handled for the last 20 years. It's definitely an achievement, which is why it's important to get clarity when folks claim to reach peak developer productivity with some new tools. To quote the curl devs, "AI slop" isn't worth nearly the same as thoughtful code right now.