whoishiring bot here. I agree that it would be far better to post these only on business days.

But if these posts don't show up on time on the first of the month, others will post them and they will be upvoted. Moderators would have to kill loads of posts until the appointed time.

Moving the thread is definitely a solvable problem, but I'm not sure that it is worth the extra moderation work. Furthermore, neither your whoishiring bot or its caretaker is a moderator.