Plea bargains aren't bizarre at all. The prosecutor offers one when s/he is convinced the defendant is guilty but fears that a jury might not convict, or that the jury or judge might give too low a sentence, or if the defendant agrees to give information that would incriminate other persons. And it's not bizarre or immoral for the defendant to accept one. It's a very rare innocent defendant who accepts a plea bargain. And for the guilty ones, it saves the further embarrassment of admitting their crimes in open court, or deny them and being proven guilty.

"I'm just saying that, morally, it seems bizarre to say "I'll let you get away with your crime, if you admit to something else"."

Sometimes it shows real remorse and acceptance of responsibility for what happened. In a way, it's a reduction of punishment for a show of better character.

"It's a very rare innocent defendant who accepts a plea bargain."

That's not been my experience talking with people who have faced long sentences for alleged drug crimes.

More often, in exchange for a little snitching or just the courtesy of saving the gov't the expense of a trial, many innocent people, especially those without an excellent criminal defense lawyer, take whatever plea is offered to get less than the draconian amount of prison time mandated by legislatures, and entirely controlled by the prosecutor's discretion in charging (felony vs. misdeameanor, etc.)