I think we both know why his "joke" wasn't funny. While the conservatives have spent several years claiming that the evidence of his collusion with Russia didn't exist, that's not true. There WAS plenty of evidence, but not enough, apparently, to make clearly absurd the Republican's plausible deniability. Their deniability was not as plausible as they pretended it to be and we all know it. Everyone also knows that if as much evidence pointed to Hillary colluding with Russia and SHE had won the election, the Republicans would have been the ones crying "treason" and their hysteria would be unmatched by anything the left has done.
Emails are always going missing in our country, and as someone in the IT field, I know how difficult that is to do. I remember George W. and the 50,000 emails that vanished in the middle of the Valerie Plame investigation, where a CIA operative was outed by a sitting president. Whatever Hillary's emails contained, it wasn't anything as damning as that famous bit of Republican party over country politics.
I'm glad that Republicans are able to laugh about all of these examples of bald-faced corruption and the selling out of our country to a foreign enemy. Clearly, their sense of humor is more acute than their sense of duty to the American people and has been for a long time. Laugh it up, the Russians are also laughing.