There is no assumption in possessing. I doubt a person would have given him his body for the rest of his life and we know with Varis that the people around Solus had no idea that he was not a human. In the short stories we have a short view from Emets side and he describes seeing his first born Garlean son as the first hopeful feelings he had, but at that time he already had sired more children.
Also strange how he can love something which is not even alive in his eyes. And again these people did not know he was an Ascian.
Yes he blames them, at least in the german version. When we are about to turn he says that we should be his weapon to punish the sinners that have hurt his people. And what gives him the right to decide that we are unworthy? Because there was once someone with more power? Because of the races not being nearly immortal? Strange how that race of unworthy beings are now having people in it that can destroy Ascians, that can defeat things like Omega or Midgardsorm. Beings that managed to use time travel which is something even the Ascians never achieved? When they new more about the crystal tower than Emet who let it be built?
What about the Garlean people? Are they lesser people to us because they cant use magic at all?
In the end before the sundering people were already against that too. People with whole souls, people who would be alive at that point and directly from his race. And at the end of their goal they would mass sacrifice a source with people with complete souls and yet he still would not care.
About Ardbert and his group: I already posted about that in this thread but the two big differences between them: They felt horrible about this at every way while the Ascians show not a single bit of remorse. And when they were shown a better way they took it and tried to redeem themselves afterwards. His friends turned their aether in to stop the flood and Ardbert after suffering for 100 year gave up his soul part to us.
A note: OMG story was when Cid was still alive, at that time they only made a plan for a possible time travel and left it for the future generation to decide if they want to do it. People were first not willing to help them in any ways but after they have heard about this maybe helping us they came and helped because we touched their lifes a lot. 200 years after that, the world was not better, seemingly might have even died somewhere. It was then, generations later, thus with people that probably had no emotional attachment to us, that they decided to use the plan. I do believe that this was done because there was no hope of it ever getting better. So in that way they were more like the original Amaurotines who saved their planet. We dont know if people wanted it or not, that is pure speculation.
No they dont need to if the story it play in has different standards (but in a discussion your own values will be part of it because that just how we work) but FF14 world is quite similiar to ours. Heck its often even more idealistic and good than ours, especially when it comes to people somehow forgiving bad things in quite a short amount of time.
In FF14s own lore murdering is bad, using genocide is bad, using chemical weapons is bad. One scientist was sentenced to death because of his horrible tests on living being even when his memories were gone. The scions and our character are kinda the moral compass the story is going with. And they are shocked and against the things that the Ascians do. Minfilia who needed to be reborn and take over these young girls was devasted about her actions and did not want to do it. You may want to take away our morality so you can argue better in favor of those characters you like, but you cant ignore the ones ingame. And they are like ours in that way.
Genocide / omincie is bad and horrible and one should let go of the past and walk forward to make a path for those that follow after.
And nobody ever said that you cant like characters. I like emet selch as a character himself. But he is no rival, he is no tragic hero. He is a villian and for some a monster. For others he is tragic, for others he is not. Nobody is taking away your right to like them. And again, you can have reasons but that does not magically take away your actions. The beauty of characters like Emet is that he can have reasons but still be the bad guy until the end. Where he does not get a talk and turn around and everything is fine. Were he can be someone that is not your cartoon evil villian but who is still not good. Who we will kill and not need to feel bad about it but can still also feel sad on why it had came that way.
I loved Caius in FF13-2. He was a great villian. Just like Emet he had his reasons and you could understand him but he still needed to be stopped.
In the end you are also not unbiased. Nobody is, especially not about game characters they like or dont like. So a topic like that will always be subjective and will probably never have a full agreement either. And I think some might find it a bit creepy how fast some people are ready to forget the actions the character did as long as he is in some way a bit sympathetic or funny or charismatic. You can of course still argue like that, but one should be ready to have people disagree with it.