Is wearing a flag patch on a backpack against regulations?

I stand corrected although Wich flag was unclear. Flags of other nations should be.

No

Had one on my assault pack, and ruck, what's the big deal?

Yes

No.

I meant if its a civilian backpack, not an issue item

670-1 does not state either yes or no, so go for it.. Show your pride. What's the worst that could happen...

Yes, inappropriate use on personal field gear.

Not one to talk. I was a draftee. Rules and regs were sort of foreign territory for me. I thought you new guys were wearing the flag patch backwards all these years.

No