Self-incrimination-the difference between Jewish and American law TB Ketubot 18

Today’s daf TB Ketubot 18 discusses establishing the validity of a document- Kiyum shtarot-קיום שטרות. When are witnesses able to invalidate a document they signed? According to Rami bar Ḥama understanding of the first half of Mishnah, there’s only one reason when the witnesses can invalidate the document.

“MISHNA: With regard to the witnesses who said in their testimony to ratify their signatures in a document: We signed the document and this is our handwriting; however, we were compelled to sign, or we were minors when we signed, or we were disqualified witnesses, e.g., we are relatives of one of the parties, they are deemed credible. Since the document is ratified on the basis of their testimony, it is likewise invalidated on the basis of their testimony (The mouth that prohibited it, i.e., ratified the document, is the mouth that permitted it, i.e., invalidated the promissory note-הַפֶּה שֶׁאָסַר הוּא הַפֶּה שֶׁהִתִּיר.)…

"GEMARA:…Rather, when the statement of Rami bar Ḥama is stated, it is stated with regard to the first clause of the mishna, that if there is no independent corroboration of their signatures they are deemed credible. Rami bar Ḥama said: The Sages taught this halakha only in a case where the witnesses said: We were compelled to sign the document due to a threat to our lives, as in that case they do not incriminate themselves. However, if the witnesses said: We were compelled to sign the document due to a monetary threat, they are not deemed credible. What is the reason that they are not deemed credible? It is based on the principle: One does not render himself wicked, and self-incriminating testimony is not accepted.” (Sefaria.org translation)

I am fascinated by the difference between Jewish law and American law. In American law a person does not have to incriminate himself. He may invoke the Fifth Amendment (see: https://www.youtube.com/shorts/kGjoJinSWnQ). I’m sure you either saw or read how witness after witness, who are Trump’s allies spreading the lie that the election was stolen, invoked the Fifth Amendment when testifying in front of the Jan 6 Select Committee investigating insurrection. Although pleading the fifth doesn’t look good, one may not draw any guilty conclusions concerning these witnesses. However, we know from all the police TV shows and movies we’ve seen, “anything you say can and will be used against you in a court of law.” In other words, a person can incriminate himself. Sometimes the police will use methods to trick or induce a person to incriminate himself (see: https://www.youtube.com/shorts/4p44xf3cPrs).

In Jewish law a person cannot incriminate himself period or in the words of the Gemara “One does not render himself wicked- אֵין אָדָם מֵשִׂים עַצְמוֹ רָשָׁע”. Any self-incriminating testimony is rejected as if it was never said.

Which system of law you think is better?