"Be damned" here indicates strong unconcern about the thing being (possibly) damned. "Let them be damned, I'm doing it anyway", etc. Regardless of the fate of X, even if X should be subjected to the worst possible fate, you will continue with your course of action. Thus, there are various ways to restate the entire phrase:
I'm going to ask this question on StackExchange, regardless of the consequences!
... despite the moderators!
... and let the moderators do what they will.
If those aren't quite emphatic enough, you could always use a non-word:
... irregardless of the moderators and their draconian rules!
Using double negation for emphasis is surprisingly common in colloquial English, despite the keepers of the language repeatedly telling us how illogical it is. You will tick people off, but maybe that's a desirable outcome.