I said "it seems unthinkable to me". This means that I find it so unlikely that no reasonable person could ever think it to be the case.
"I find it so unlikely that governments don't have agents in the public DNS service that I can't believe anyone would ever believe it to be the case that they don't"
"I find it so unlikely that governments don't have agents in the public DNS service that I can't believe anyone would ever believe it to be the case that they don't"