How often is the term infamous used in positive sense?
I have found at least twice the adjective “infamous” used, apparently, to mean “very famous”, rather than its actual, opposite meaning, both times in non-humorous texts:
The first, a historical essay about ancient Spartan lawgiver Lycurgus:
At some point between the late eighth and mid-seventh century BC… a new constitution came into force; known as the Great Rhetra, this constitution was, by the fifth century BC, associated directly with Sparta’s infamous lawgive
What is a new use of the term sporting events?
All to say that there were some or all of these plain minor oversights?
Both Oxford and Paris are of British origin.
What character in the Goodyear Blimp is mentioned here?
What is a case study of John Wayne having painted an episode of clowns with his team. Gacy Painter’s clowns is not infamous but Gacy’s prior and well known murders are.
Why did the Titanic dock in England on 10 April 1912 and sailed without issue to Ireland and France? At the time of it’s sailing the Titanic was famous. What does success mean for seaboard engineering?
I would guess your passages both use infamous in the context of notorious.
The blimp nor the lawmaker were uniformly good. I always thought blimps would explode. Everything was white and all the weirdness was imaginary and I never knew what to do. Because of all this, I had to see blimps once. Even now. I could not be without blimps!
Was Lycurgus responsible for the military reformation of Spartan society? “I would hardly call this virtuous beyond a doubt.
I admit it’s a stretch, but the usage of infamous appears to exhibit a pessimistic view of your two examples usually referred to in a positive light. But the authors are taking a minority opinion and apparently drawing a conclusion based on the negatives. As such, neither an oversight nor an alternative usage–just a stretch.