No the author didn't read the methodology of the Stack Overflow Survey nor did they notice they can get the historical CSV of the survey going back to 2011 [1] which literally tells the number of respondents per language (as-in how popular it is; no secondary population from TIBOE needed). Nor do they seem to understand (unlike you who does understand) that Loved and Dreaded have very specific meanings.

They did shoddy work and I'm calling them out on it. They very easily could've tried to use the past (then) 9 years of data to show that as a language gets more popular it became less loved; but they didn't.

The question of "If Java and Ruby appeared today, without piles of old rails apps and old enterprise Java applications to maintain, would they still be dreaded or would they be more likely to show up on the loved list?" is answered.

It's a no. For 2020, Ruby was 4.5% and Java was 8.8% of developer's "Wanted" languages while Go (17.9%), Rust (14.6%), TypeScript (17.0%), Python (30.0% !!). Sure a lot of people would like Ruby and Java (there already are actually a lot of them) but when you're not at the top of the Wanted it's going to be very hard to get to the top of Loved.

[1]: https://insights.stackoverflow.com/survey/