Go's selling point is most definitely performance, but relative to implementation effort of a given application. This is opposed to languages that focus more on maximum performance at any cost to implementation, or maximum convenience at any cost to performance.
It's not the kind of performance expectations where processor-specific SIMD support really matters (although nice if it's there)
Go's performance goals are to have much faster runtime than any interpreted language and faster build times than most compiled languages. It's a reasonable stance.
Basically a political answer that answers nothing.
It isn't performance compiling, as that is only surprising for those that never used 90's compiled languages like Modula-2, Object Pascal, Clipper and co.
It isn't performance of code execution, as even GCCGO could beat the reference implementation, unfortunately now stagnant since no one cares to update it beyond Go 1.18.
And to go back to the article, as pointed out there,
> The Go toolchain does not currently generate any AVX512 instructions.
Edit: to address your literal remark: so even the title is correct, if you think of a programming language as more than its syntax.