[sleepysysadmin]

Never criticize. It will never work or be beneficial at all. No point even going to your manager. It's not your problem and you haven't been asked to help. Furthermore, it's your manager's job to fix this and they too aren't doing their job. When you criticize you will be criticize them as well.

I've been in your position many times. The big problem arrives is when incompetent and useless coworkers start unloading their work onto you. I have been in this situation many times as well. The best advice here is to never lie. Never 'cover'/lie for said coworkers.

Oh another rule, never let any coworkers know how much work you do. You arent just avoiding bragging, tons of benefits down this line. Could be the case of what's happening here.