On the contrary, her motives and declarations have been examined and countered a great many times - particularly in a joint community project where a number of lore enthusiasts came together to source their discussion points in one great, big analysis in the form of a video essay focused on Venat herself.

After spending a significant time posting the same sources across a number of different threads and seeing them dismissed or conveniently forgotten about a few pages later.

The video in question can be found here, with perhaps the most relevant section being the one aptly titled 'excuses':

https://youtu.be/fsk412wCrJY?t=1101

It's admittedly a long video so it might be worth watching it in chapters but everything is sourced from the game itself, various lore related interviews and short stories. I don't know where this idea that the people countering Venat's motivations aren't equipped with sources is coming from since it only takes a look through the post history of someone like Rulakir or Lauront to see that, yes, they do source a lot of their talking points and explain their reasoning and conclusions clearly.

Anyone is of course free to like and support 'cRyStAl MoMmY' but her motives are so paper thin and contradictory that they do not hold up under the slightest bit of scrutiny and they certainly wouldn't be accepted as something to cheer on if they were aimed at the Scions and their loved ones and civilisations as opposed to being inflicted upon the Ancients. Nor would most accept it being inflicted upon any of us in the real world, for that matter.

It doesn't help that - as myself and a handful of others have pointed out many times - it was common here for certain posters to embrace the stance prior to Endwalker that no matter how sympathetic the reasoning or desperate the circumstances there is supposedly never a justification for acts of genocide. Which mysteriously fell to the wayside as of Endwalker's revelations and this is all just really a last ditch attempt to try to cling to the idea that, yes, it was all very sad but it 'had to' happen and/or Venat 'tried' and 'had no choice'.

It's not controversial at all to point out that if she was deliberately withholding information from her people, allowing a disaster to strike and kill large swathes of individuals and also working to turn others against them then that was not making a genuine effort to save them. That is serving the role of an antagonist and saboteur.

Preserving mankind by wiping out the Ancients through an act of deliberate genocide and then replacing them with complete different species in a twisted form of eugenics doesn't really count as preserving mankind, I'm afraid. Which in itself is the main point of contention.

...but even putting all of that aside, the game chose to lean on some of the most lamest and controversial plot devices including mind wipes and time travel. It is being criticised for such as well, since such plot devices rarely lead to a consistent narrative. Then there's the numerous retcons that conveniently change established rules but only in favour of the protagonists which is also being called out.