if blah {
     ..
   } else {
     ..
   }

> Maybe that's popular in some obscure places, but it is weird they made that the only valid syntax.

That is valid K&R syntax[0], which is used prevalently in C (e.g. Linux kernel). FYI, Rob Pike wrote a few books with Brian Kernighan (the K in K&R).

Go is designed for consistency and optimized for the compiler (e.g. mandatory braces, no unused import statements). Declaring a single canonical format (e.g. gofmt / PEP 8) solves a lot of syntax bikeshedding.

[0]: https://en.wikipedia.org/wiki/Indent_style#K.26R_style