Not trying to offend or be snarky, but I think the point that is confusing is the idea that, it was stated that Twitter is a mess and contains a large amount of incorrect information, which seems to be the chief complaint noted. Yet, the way you state that we can refute that it was a left wing propaganda tool is that Twitter did it's own internal research and found the opposite to be true. So, Twitter is full of lies, but when they tell us something about their own data set, we should take that as gospel because a google search will be able to tell us that they said it was fact. So, we should believe that. It feels like asking OJ if he killed Nicole and Ron. Everyone thinks he did, but he said he didn't, so end of story.
I just feel like it has always been a bit of a mess filled with disinformation. The problem seemed to be that they were previously censoring a lot of the conservatives on Twitter, but seemingly not doing the same to liberal users.
So, if I do not trust Twitter to be an honest source of information, telling me to google search Twitter's internal investigation into their algorithm will not offer reassurance or give further confidence in Twitter (because I would presume them to be liars if that is how I feel about their integrity). I believe that is a valid argument.