You're not wrong, but you do still have to swear an oath to uphold the constitution. Also, the bar exam doesn't test your ethics, or even your ability to practice law. It tests your ability to memorize a ton of shit you'll never use in your actual practice. Maybe it was useful once upon a time before every lawyer practiced in a specialized subset of law, but mostly it was made to stop people of color practicing law. (https://www.sandiegouniontribune.com/opinion/commentary/story/2020-12-07/abolishing-the-bar-exam-bias)
It really needs to be reformed, though I would actually be in favor of abolishing it and having the third year of law school be reformed into an apprenticeship model where you learn directly from an experienced attorney. Or a specialized bar exam that tests for the area of law you want to practice. Something needs to change about it.
I'm getting off topic. Yes this guy is a fraudster and so is everyone who advised him to sign, but it has nothing to do with whether anyone took the bar exam.
Source: am lawyer in Wisconsin (who actually took the bar exam)