How much of a reliable source is Business Insider as opposed to... say something like Newsweek? Do they publish hearsay and wishful thinking, or do they corroborate with sources?
They are just using the Institute for the Study of War as their source - and they are the main source used by most western media articles on the war in Ukraine. The ISW basically analyze all the available open source data (videos, Russian milbloggers, etc.) to compile daily reports and map of the front lines.
They're quite good, I check in on them directly regularly. After a while you notice the news articles are just regurgitating their daily reports.
He's just saying that Business Insider was using the think-tank info, and provided a direct source, so you can check their info directly.
Then again, many media outlets use and quote other sources. Nothing strange imo.
Also, basically the nuance some ppl are giving in the comments is that in the end of the day a think-tank is giving an analysis from their lazy confi chairs, and are not in the frontline, and for that matter any analysis is not necessarily" the truth". But this think tank is of good repute, imo.