He's suggesting that not mounting it as read-only by default will break a few things like grub-install, but promptly suggested editing /etc/fstab to mount it read-only by default.
So... his own solution to the problem is to mount it as read-only.
The hard drive analogy is ridiculous because while you can lose data you cannot brick your hard drive or computer by erasing it. There are ways to brick a hard drive by corrupting the firmware but there are very specific tools like "hdparm" that you have to use to do it, not an everyday command like "rm".
This makes me wonder why Linux only has a single "root" user rather than multiple types of administrators. Windows, for example, has Administrator, which can do nearly everything, but some files and processes are protected under SYSTEM or TrustedInstaller. If you REALLY want to, you can still remove those files by changing ownership, or launching a command prompt with SYSTEM permissions, but it does add a significant hurdle to doing things that could cause significant damage.