The constant turnover, complete lack of work/life balance, and extremely poor management leads to a team that burns out quickly, time and time again. Team members consistently try to do (more than) their best, put in countless extra hours (on a regular basis), and are met with complaints that it is not enough, not right, etc. Letting go of hard-working employees only continues to hurt the department.
Management of the department is the biggest issue here, by far. Swearing at staff, bad-mouthing team members to others behind their backs, favoring certain employees because they say yes to everything asked (no matter how unreasonable/unprofessional), determining a certain employee is suddenly at risk of losing their job (there is always one at any given time) and making it somewhat of a mission to get them out the door... the list goes on. Totally unprofessional, and results in a toxic work environment.
These issues and more have been repeatedly reported to HR in the past, and the cycle of no action has apparently continued and good employees have continued to leave as a result.