Of course, Putin doesn't give two shits about the MAGA supporters rotting in a DC dungeon. He's just gleefully pointing out the civil rights violations of the U.S. and the wanton murder of a protester (Babbitt) by a still-unnamed Capitol cop, who won't even be charged per the DOJ's "investigation" back in April, I think.
It's called hypocrisy, and Putin is calling attention to it.
Of course, nothing really compares to the harshness of Putin's Soviet/Russian gulag system, and there is plenty of blood on Putin's hands. But that doesn't stop him from pointing out how hypocritical the current administration is.