So true. The Spectre and Meltdown flaws have nothing to do with the abstract machine that a processor implements. You might as well claim that the vulnerabilities are the result of the ISA (which itself was born to smooth over differences among machines). Rather, these vulnerabilities are the case of a confused deputy. There is nothing to say you should not speculate, just do not do so across security boundaries leaving breadcrumbs for an adversary to discover.