Very perceptive, lilyyang!
Figuratively, the adjective ‘bankrupt’ means that one is completely lacking in a particular quality, namely when someone is said to be “morally bankrupt.” It may be precisely because of this figurative meaning that some people try to avoid saying, “I am bankrupt” and instead say, colloquially, “I am bankrupted,” because saying, “I am bankrupt” might carry the connotation “I am morally bankrupt.”
Typically as a verb, ‘bankrupted’ is used in the active voice to express that something or someone caused a person or entity to be reduced (or nearly reduced) to bankruptcy. For example, “Mayor Richard M. Daley nearly bankrupted Chicago,” i.e. he nearly caused the City of Chicago to be driven into bankruptcy.
“I am bankrupted” means “I am reduced to bankruptcy,” so I agree that it would be best to say, “I have been bankrupted,” i.e. “I have been reduced to bankruptcy.” You are correct to note that this is passive voice: I have been bankrupted (by someone or something that is unnamed).
This problem of using the simple present “I am” form of the verb ‘to be’ versus “I have been” with the past participle (for example, “I am detained” versus “I have been detained”) is not so problematic in other languages, but it certainly is problematic in English and should be avoided, unless or until you become familiar with specific colloquialisms. For example, “I am drugged” has a completely different connotation than “I have been drugged.” “I am drugged” can colloquially mean that I have taken a fair amount of drugs or that I have been given sedatives by the doctors, whereas “I have been drugged” means that someone else has caused me to ingest drugs without my knowledge.
More often than not, a person who says “I have been bankrupted” is not speaking literally, as if to say, “I need to legally file for bankruptcy,” but rather that their money supply for the month has run low. For example, “I have been bankrupted (by) buying my friend a birthday present.”
I haven’t seen this particular TV show or episode, but judging from the still, I get the sense (perhaps incorrectly) that, if the character in this scene is talking to a lawyer and colloquially declares, in the literal sense, “I am bankrupted, completely,” he is probably expressing that he has come to realize that outside forces have (suddenly) caused him to (very soon) become indigent. One possible scenario might be, “I have been accused of this crime which has caused me to have to spend all my money on lawyers to establish my innocence. This will bankrupt me.”
When you say, “I’m (completely) broke,” it typically means that you have (temporarily) run out of money, not that you are completely indigent. I remember as a teenager, if one of my friends were out of money, they would sometimes joke, “I am from that post-Renaissance period called baroque.”