Yes. I initially thought that the post makes a subtle point along the lines of "if you can show that a system can solve all problems in a domain for a parameter

Yes. I initially thought that the post makes a subtle point along the lines of "if you can show that a system can solve all problems in a domain for a parameter choice, that doesn't mean it can solve all problems in the domain for the same parameter choice". However, this is clearly trivially true, and it and doesn't mean that it may not be advantageous to map a problem from problem space to system parameter space. Hence, I fail to see how this would be a scam in general.