obviously you all
No, what is obvious is that you misunderstand.
That SQL statement (with the LIMIT phrase) is only there in that post to quickly and roughly show the content of the table, by way of showing the first few rows.
obviously you all agree that 10_000_000 JSON is not possible to send between server and client
I entirely disagree.
Of course it's possible. I've done that by accident on a few occasions before (selecting "show all records" on a huge log table). It's not smart and it certainly takes a while. The parser here isn't the only problem, sending Gigabytes of data over the office network for every page refresh is damn slow and generally you get shouted at a lot for overloading the network yet again.
perl -e 'use Crypt::Digest::SHA256 qw[sha256_hex]; print substr(sha256_hex("the Answer To Life, The Universe And Everything"), 6, 2), "\n";'