Doesn't that simply create an exploitable hole that allows for hacks and cheats that would just weaken bitcoin overall?
No. Bitcoin works with or without LN.
What I mean is, if LN's lack of redundancy allows for hacks and cheating transactions or some kind of weak link... wouldn't it weaken bitcoin, in general?
People will lose money
from bitcoin because LN was hacked in some way, and they won't blame LN... it'll just fall on bitcoin. That's how the media and people's minds work. There will be headlines like: "For the first time, Bitcoin gets hacked" or whatever. You know how FUD operates.
But if LN's ledger system is as infallible as bitcoin's, then I guess there's nothing to worry about.