Some people value
time. Doing 55 or 65 vs 75 while on a significant trip equates to dozens of minutes or halves of hours or more. Your welcome to crawl along at your own pace, though. Time is one thing you can never get back in life.
Also
"Of course, going even one mile per hour over the posted speed limit is a crime. This is not an opinion, nor is it open to interpretation." -this is false.
California:
Speed Law Violations
22351. (a) The speed of any vehicle upon a highway not in excess of the limits specified in Section 22352 or established as authorized in this code is lawful unless clearly proved to be in violation of the basic speed law.
(b) The speed of any vehicle upon a highway in excess of the prima facie speed limits in Section 22352 or established as authorized in this code is prima facie unlawful unless the defendant establishes by competent evidence that the
speed in excess of said limits did not constitute a violation of the basic speed law at the time, place and under the conditions then existing.
You can exceed the posted limit and not be in violation. Per the same, though, you could be driving at the posted limit in rain/fog/blizzard and be in violation of speeding. Common sense is required.
Driving efficiently is fine - taking it to a whole religious style belief system is beyond me. The article is preaching and as such you will find believers and non-believers. I'm in the latter.