Specific points that you'd want to address if you were purporting to rebut Hyperloop criticisms:
* Because Musk's plan can't leverage existing last-mile infrastructure the way HSRs do, it delivers riders from one very inconvenient location to another, adding 1-2 hours of additional transit time to SF-LA.
* Because (by Musk's own admission) destructive disruptions of his pod-in-tube runs are catastrophic in a way that they aren't with HSRs, his plan requires TSA-style airport security, adding an additional 15-30 minutes to every trip.
* The cost estimates for the Hyperloop captured only its capex costs and not its operating expenses, so that the per-ticket prices derived from its proposed cost bore no relation to its actual cost structure.
* That the tunneling and viaduct cost estimates given in the Hyperloop proposal were so low that they constituted a revolutionary breakthrough in urban planning and structural engineering in their own right; in other words, if he can dig a Hyperloop-capable tunnel for the price his plan suggests, or run an elevated tube as cheaply as he suggests, why waste time with Hyperloops? The answer would be that he can't do either of those things.
* That the routing he proposes, particularly with regards to mountain passes, are wildly optimistic, and that a realistic routing will result in a longer run and significantly increased costs.
* That the forces involved on passengers in the Hyperloop exceed the tolerances allowed for existing HSRs in ways that are likely to make motion sickness a signficant problem.
This article appears to address none of them, and your comment appears to be premised on the idea that those criticisms hadn't been made.