You may not be wrong but the authors were just picking an example in the headline. In the analysis they calculate t0 as 2026.87 plus/minus 5.50 years. They clearly state what assumptions that is based on do not take it as absolute fact but as providing thought for discussion.

Highly recommend "When We Cease to Understand the World" by Labatut, a lot of it concerns the different strains of apocalyptic thinking among the early 20th century scientists.

> even in 1960 some were thinking about that "there may be a fixed date of end of the world"

I think this can be taken 2 ways.

1) This is more an instance of "see clickbait was a thing in 1960"

2) There have always been and will always be people that believe that. See 2012 or a random person on the Las Vegas strip preaching it.