No, harping on how "general shell Linux access equals root" means that if you try to avoid giving malicious code shell access then you'd be safer.
I.e. "sandboxes are vital, not just a good idea".
>however there are systems that are less secure than others.
Not really. There are systems that are targeted differently.
I'd even argue that Windows with a recent antivirus is more secure than Linux.
>OpenBSD is one of the better ones (assuming you can actually live with the small feature set supplied)
OpenBSD is mostly guarded by the Elusive Joe effect ("Why is he so elusive, does he ride fast or is he a sharpshooter? Nah, nobody cares about him").