More like robbers rob a bank and take hostages. They threaten to kill a hostage, but still don't get any money. So they threaten to report the bank for not being up to code with an expired fire extinguisher if they don't get some money.
They know the bank doesn't give a shit about hostages being killed. But a few pennies for a minor fine is a threat the bankers really understand.
Those instructions are from the official docs, and install.sh comes from the source repo. It's an annoying script (it basically runs apt, npm, make, on your behalf...thanks, I can do that myself), but if you're trusting the repo source to begin with, I don't think it's any less secure.