Each story is present it a few places - sourced mixed to reduce bias. We may never know what was the scale of the influence, so that's the debatable part. But unless someone claims that popular social media accounts have no influence over the results, they agree that IRA did play a part.
You could also speculate that IRA is not led by silly people eager to waste government money for internet LOLs. If their efforts were not effective, why do they continue that for years?
Either news agencies don't influence elections or fake "news accounts" did: https://www.bloomberg.com/news/articles/2017-12-05/how-the-k...
Some review of IRA-run accounts featured in popular news outlets: https://www.researchgate.net/publication/323703483_The_Twitt...
Either celebrities don't influence elections, or IRA accounts like ten_gop did: https://www.thestar.com/news/world/2017/10/19/how-ann-coulte...
More detailed story of a specific post-election hashtag: https://www.politico.com/magazine/story/2018/02/04/trump-twi...
And of course there's the cozy bear / Dutch agency episode, confirming the source of some documents releases to wikileaks: https://nos.nl/nieuwsuur/artikel/2213767-dutch-intelligence-...
Each story is present it a few places - sourced mixed to reduce bias. We may never know what was the scale of the influence, so that's the debatable part. But unless someone claims that popular social media accounts have no influence over the results, they agree that IRA did play a part.
You could also speculate that IRA is not led by silly people eager to waste government money for internet LOLs. If their efforts were not effective, why do they continue that for years?