The author does not claim that these attacks currently allow to break all processor securities. He just points out that two new side channels are possible by ex

The author does not claim that these attacks currently allow to break all processor securities. He just points out that two new side channels are possible by exploiting AMD optimizations then it demonstrates their feasibility on already known and fixed attacks. But beware, what is already known/fixed and requires to disable patches are the attack scenarios and not the 2 new side-channels described in the whitepaper! Maybe there are unknown scenarios where they could be used, who knows? Finally he suggests some countermeasures. So, no, it's not a nothingburger at all. It is a detailed research work that anticipates a potential issue, suggests solutions and explains undocumented processor features.