This all really depends on the maturity of the organisation and the team.

"1 hour SLA would be astonishingly, irresponsibly fast". Yes this can be true for a lot of cases, but at the same time it's nothing 'astonishing' or 'irresponsible'. Again it just depends in what state and maturity level the team and organisation are at.

Also, I think you are talking more from dev side of things? Would that be a good assumption to make? If that's the case then your points are very valid, but don't forget a lot of ops-like-teams work on code bases significantly smaller than coding projects and as such that SLA is totally fine.

Let's also remember that an 'SLA' for a review should be a guideline, not a factor to be always meet. There are always factors that will influence this.