I get that they'll want to avoid the embarrassment of imprisoning their former president. But aside from the fact that I think having Trump as a president has been seen as a massive embarrassment anyway worldwide, if they don't make a very firm statement that it's not ok to sow widespread doubt on a presidential election with no proof, then every president can try to pull this when they lose.
And at this point protests and conspiracy theories may run rampant even if that person doesn't make direct accusations, because the damage has already been done to people's trust in the system, if there are no consequences for Trump.
You basically make a martyr of him if you throw him in jail. You would basically fuel a large segment that he was witched hunted for for what he has done instead of just showing how baseless his attacks are. An ex president in jail does not solve anything and it would not suddenly make the people who follow him suddenly drop him.
Right, but it wouldn't be about convincing his cult following. It's about preventing future presidents from trying to pull the same stunt, since it would have no legal consequences.