That comes after very in-depth reading. What got me that far to even trust their judgement that this kind of research would be worth my time was the fact that they were consistently right about takes on the USSR that seemed ludicrous. Just that they seemed to really know their stuff about USSR history especially the Stalin era. So I started reading

Michael Parenti - Blackshirts and Reds

a rather short book about anticommunism in the west. I already had very left views but what stuck with me was that I required a revolution to be "perfect", the outcome sure and everyone had to be happy, an unrealistic standard considering the kind of fundamental change I envisioned. Or in Parenti's words:

The pure socialists’ ideological anticipations remain untainted by existing practice. They do not explain how the manifold functions of a revolutionary society would be organized, how external attack and internal sabotage would be thwarted, how bureaucracy would be avoided, scarce resources allocated, policy differences settled, priorities set, and production and distribution conducted. Instead, they offer vague statements about how the workers themselves will directly own and control the means of production and will arrive at their own solutions through creative struggle. No surprise then that the pure socialists support every revolution except the ones that succeed.

Once I had conceded my previous "anti-tankie" views and thought of the USSR not as a failed revolution that started of well-intentioned but was led astray by power hungry dictators, but as a successful revolution that had to endure a constant onslaught, physical as well as political, I was "through the looking glass" so to speak.

Then the genocide in Gaza happened and I kind of looked at the countries we were allied with, who were consistently some of the worst offenders of human rights. The whole supporting violent dictatorships in former colonies wasn't news to me, but when put into perspective I had a "Damn we really are the baddies aren't we" moment.

I realise that this doesn't answer your question on Ukraine and the Uighurs but that's because I don't have the time right now to get into a debate on that, and the original question was on what changed my mind about it which was less the actual research I then put into, but the heavy-lifting on even questioning the western narrative was done before that.

To answer your question in a nutshell however: The reason the situation in Ukraine deteriorated this far, to the point that the ethnic russians in Ukraine had to even put up "self-defense" forces was meddling of western capitalist forces. The article that I keep referencing on that is ( CW for pictures of dead bodies and gruesome descriptions of fascist violence):

https://covertactionmagazine.com/2022/07/29/what-the-u-s-government-and-the-new-york-times-have-quietly-agreed-not-to-tell-you-about-ukraine/

The open fascism in the paramilitary groups that later got put under the umbrella of the Ukrainian army was an open question mark for me, this article gives a very detailed answer to that. The details in that report post 2014 are corroborated in the UN reports as well:

https://www.ohchr.org/en/documents-listing?field_geolocation_target_id%5B1136%5D=1136&field_content_category_target_id%5B180%5D=180&field_content_category_target_id%5B182%5D=182&field_entity_target_id%5B1349%5D=1349&field_entity_target_id%5B1350%5D=1350&sort_bef_combine=field_published_date_value_DESC

As for the so-called "genocide" of Uighurs in China, the "evidence" is very very circumstantial especially considering the scale alleged. Millions of people are alleged to be held in internment at some point, a scale that should be visible from space. I mean manhattan has a population of 1.7 million, where are all these people interned?? As an example of one of the oddities about the whole allegations. The only countries that seem to care are outspoken anti-communist countries, with the whole muslim world not considering the crackdown on religious extremism in Xinjiang a genocide. All the articles I kept getting linked were "oh how terrible the situation there is, what an evil evil government" with no one seemingly caring about the actual people. It's all just treated as an abstract talking point. And the only references boiling down to two reports by Adrian Zenz

https://www.tandfonline.com/doi/full/10.1080/02634937.2018.1507997

https://www.tandfonline.com/doi/full/10.1080/02634937.2021.1946483

a person with some questionable viewpoints

https://books.google.de/books?id=lRtSQB3HHJcC&printsec=frontcover&hl=fr&redir_esc=y#v=onepage&q&f=false

All the stuff around it seems to be pushed by Washington based anti-communist thinktanks trying to establish an "east turkestan". The whole movement is heavily US-financed. See here for more info:

https://hexbear.net/post/2361

That's what changed my mind about it all anyway, but like I said I probably will not be able to go into more depth about this, as I have spent too much time on this already.