Needless to say, Tsarnaev is probably the single most hated figure in America now. As a result, as Bazelon noted, not many people will care what is done to him, just like few people care what happens to the accused terrorists at Guantanamo, or Bagram, or in Yemen and Pakistan. But that’s always how rights are abridged: by targeting the most marginalized group or most hated individual in the first instance, based on the expectation that nobody will object because of how marginalized or hated they are. Once those rights violations are acquiesced to in the first instance, then they become institutionalized forever, and there is no basis for objecting once they are applied to others, as they inevitably will be (in the case of the War on Terror powers: as they already are being applied to others). As Bazelon concludes:

No one is crying over the rights of the young man who is accused of killing innocent people, helping his brother set off bombs that were loaded to maim, and terrorizing Boston Thursday night and Friday. But the next time you read about an abusive interrogation, or a wrongful conviction that resulted from a false confession, think about why we have Miranda in the first place. It’s to stop law enforcement authorities from committing abuses. Because when they can make their own rules, sometime, somewhere, they inevitably will.

Leave aside the fact that Dzhokhar Tsarnaev has been convicted of nothing and is thus entitled to a presumption of innocence. The reason to care what happens to him is because how he is treated creates precedent for what the US government is empowered to do, including to US citizens on US soil. When you cheer for the erosion of his rights, you’re cheering for the erosion of your own.