Thank you for clarifying. I thought for a second it could have been a grammatical nitpick but discounted that since this thread is re: an Antirez post. I personally would be very sad if his writing style became more forced and began to feel like excerpts from The Elements of Style.

This page [0] seems to suggest that "less is also used with numbers when they are on their own and with expressions of measurement or time".

Lines of code is surely a measurement, which makes the use of 'less' here acceptable.

0: http://www.oxforddictionaries.com/words/less-or-fewer