Big Questions

Definitely, the fossil fuel lobby hates large dams !
The study by Ansar et al. completely ignores the climate change problem. They promote fast built fossil fuels plants instead . Their statistics are biaised since they forget that the main use of large dams is not power production but food production! (storing water to feed irrigation systems).
I think your panel of commentators is not equilibrated at all since they all share a common hatred against dams. IHA has published an answer here : https://www.hydropower.org/news/2014/the-benefits-of-sustainable-hydropow... and ICOLD will soon publish a more complete one.