The statement "X can do what they want with their Y BUT they shouldn't because Z" is ceding to X that which was already his, and in the same breath revoking that cession. Essentially: They don't have to change it, but they should change it.
Consider instead: "BUT this isn't what I'm looking for in a community, and it's not a community in which I will continue to participate - I encourage others to do the same."
That statement would have both acknowledged the owner's right and done so without attempting to indirectly dictate what the owner should do with his property.
If you have a better way to shovel stuff in bags, the most efficient and profitable way to implement "shovel stuff in bags 2.0" is to convince the guy in charge of 1.0 to upgrade, not go to the immense effort of creating a competitor, or start shoveling yourself. At least not as the very first step.
If you want to make a competitor, just do it, you don't need "cover" of some minor 1.0 vs 2.0 issue. Either way its not workin.
"Hacker News is a privately run site and nobody's under any obligation to change how they choose to run it. But the focus on avoiding conflict to such an extent that controversial stories receive less exposure than ones that fit people's existing beliefs doesn't enhance our community. "