"And why exactly shouldn't the guy who's invested in the best hardware have an edge? Should perhaps we also mandate that all software engineers use exactly the same 2004-era Acer Pentium 4 laptop so that any difference in productivity is strictly due to programming skills?"

Apples and oranges. Should we also mandate that doctors only use scalpels?

Any analogy quickly becomes ridiculous as soon as you compare HFT to anything of actual use in this society.