I think even Putin was surprised about how unprepared and just plain dumb Trump is.
Trump said it was an “incredible” suggestion because he loves the word incredible - it is one of the few words left in his rapidly shrinking vocabulary. The other part of this is he had no idea what Putin was actually suggesting and he certainly doesn’t know any of the details about who Bill Browder is or the actual purpose of the Magnitsky act. His understanding of the complexities of our relationship with a man who serially murders his enemies is limited to the point of a hog staring at a centrifuge. It really is nothing except whether Donnie is getting the endless amount of attention and love that he craves.
Toddlers are all conscienceless sociopaths - if they were armed we would all be dead. Trump is a toddler. People continue to be fooled by his skin suit and height, but he is just a fucking toddler staggering through a world that isn’t working the way it used to (he gets everything he wants when he wants it) and it is reaching a tipping point.