If they did mean to be heard by passengers, that's not a very professional behaviour. It's not very professional to discuss those things loudly anyway. I can understand their frustration, but it's best if they kept it between themselves. I don't think it would do themselves any favours by talking loudly about those issues - loud talking in itself is annoying in any case.

I would be a bit concerned if it were really unsafe (in my humble opinion it's not really a safety issue, but it is an industrial issue), as it suggests that the CAA regulations are set at an unsafe level then.

If they had serious concerns, they can always file a CHIRP report.