Nevermind the fact that the parent post believes its possible to quantify "exactly the right level of ambition," the poster believes that the only people that should be "allowed" to comment on whether or not something is too ambitious should be people that are currently undertaking ambitious projects themselves.
This smacks of privilege. Not everyone is or can be in a position to pursue ambitious projects. To say that these people should be barred from commentary is ridiculous.
I've not suggested anyone be 'barred' from commentary.
Rather, if you want to dump generic negativity on a real, delivering project, you should justify why your negativity is relevant, for example by documenting your own related efforts.
If you want your cynicism to be respected, then yes, that's a privilege that needs to be earned. You can always say it, but it should be called-out as empty bullshit until backed with detailed reasoning or experience.
This smacks of privilege. Not everyone is or can be in a position to pursue ambitious projects. To say that these people should be barred from commentary is ridiculous.