1.1 - Criticizing people/political systems through media outlets is nothing new. A mild example would be the US media's portrayal and ridicule of Canada and it's citizens, which I still don't understand. I am aware of the bad relations between the Canadians and the French-Canadians, but the US's ridicule does not differentiate between the two, expressing a discontent with them as a whole. But we would never turn them away, we rely on them more so than most people realize. I've seen Republicans bashing Europeans numerous times, mostly French, but we still work together.
I find no reason in "Evolvers didn't like Regulars" as means to deem them bad or hostile. (Well taking in account a republican mindset... Maybe.)
1.2 - Blown up the gate? Do you mean episode one? I'll probably re-watch the series after it finishes, if my memory is off sooner... If you do mean episode, when the humans lost and were retreating, I can speculate a number of ideas.
-The Hideauze are not aware of the Regular's location.
-Traveling normally (their way) would take too long, the regular's military base may be mobile.
-Those bunch wanted revenge for the brethren they lost.
-They wanted to spite the Regulars with the same technology they used to harm them with.
-Just because the gate is gone wouldn't mean the Regulars wouldn't make another to start up attacking again.
...and such. I'll rewatch episode 9 or 10 (and probably one) at some point, to make sure I am not missing something from the documentary. (I am remembering the "gate" as a construct at the moment.)
1.3 - What I got from the battle in the first episode, it wasn't the Hideazu attacking the Regular's area, it was the Regulars invading theirs.
1.4 - Them losing the means for human speech I would assume is a process of evolution not will. Our previous forms did not have human speech after all. Dolphins and Whales developed their own, that we don't understand. I doubt every aspect of their "rapid evolution" was predicted, at most, I would assume, maybe a thousand years would be predictable.
1.5 - This is most likely why I'll re-watch 9-10, I missed the "desire for space" part, but in terms of "capability".
-Humans are disposed of if they are not useful for military service, they are tools before individuals.
-If they have outstanding record, and survive long enough, they get a small break (I think, maybe it was a retirement, but that would be counter productive, to lay off your best soldiers ).
-Only a privilege few can live a life of freedom and luxury (from my understanding).
-They are completely useless outside their Machine Caliber, if Ledo is viable candidate for example.
-They, soldiers, seem to lack any education outside the needs for military and survival.
Granted I do not know the Hideazu's lifestyle, but from the Whalesquid example, I would assume it's not that bad.
2. As for improving "themselves", all they did was improve the environment around them and the tools at their disposal.
Just because the Whalesquids didn't display it, doesn't mean that they lost it. For all the thousand/million/billion years they've existed, they never branched out and left that facility.
If I understand correctly, dolphins share the same capacity for knowledge and intelligence as humans do. So now I am thinking of Dolphins.