Not him, but I'm guessing it's because SPARC looks a lot like the GAS/AT&T Intel syntax -- lots of 'noise' in the form of % and $ everywhere. It also has branch delay slots and not-so-intuitive operand ordering, register windows, and all the other RISC features that look like they discourage using Asm, as a big part of the philosophy was "use a compiler".
Now that's interesting. What is the deal there?