:faceplant: Dude.. x) " Or at least the kind were used to. I think there Oresians from Drews lore page "Thargoids are divided into more than one group."
Oresians Are thargoid and so are Klaxians !
Both of these groups are thargoid race ><
http://www.drewwagar.com/progress-report/elite-dangerous-lore-the-thargoids/
And Okay I can understand , in a in-game perspective you can say its not thargoid I agree with that, BUT in a lore perspective the first thargoid encounter was the same exact WAY as we have now in game !
And, can you imagine Frontier create another race than Thargoid with the fact that we Know thargoid are now Human enemies since we beat them in the first war (Again Lore perspective ! )
Anyway

Everyone has a different point of view, for me its thargoid so I will say Thargoid !
have a great day.
EDIT : I want to say for your edit that you are correct, we dont know if UP or UA are from same races, we dont know what they are.
At this right moment we dont even know if UA or UP are the reason of these interdictions!
We are assuming too much.
From my memory of the Dark Wheel by Robert Holdstock the Oresrians just looked like them. Didn;t say they were peaceful Thargoids. They had physical differences (slight differences) from memory it was their knees or something. Similar looking but not the same race.
EDIT: Found it..
" Alex stepped away, heart beating, blood rushing to his head. Compound eyes, jointed limbs, head
antennae, double cutting jaws . . .
Thargoids!
Here, on a space station!
Thargoids were deadly. Thargoid spacers had their fear-glands removed, and were considered to
be the most effective and potent of humankind's enemies. The bounty for killing a Thargoid was
huge, and for capturing and delivering the juvenile form, the Tharglet, to any Space Navy research
centre, even greater.
What were they doing here?
The Thargoids chatted together and watched Alex coldly. Alex noticed that each had an appendage
resting on its thoracic plate, where they holstered their hand-lasers.
'Back off,' a voice whispered, and Alex turned. McGreavy stood there blinking through his
deformities. Alex had not grasped how short the man was; he only came up as far as Alex's chest.
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'Thargoids . . .' he whispered.
'Bull,' McGreavy said, and dragged Alex away. 'They're Oresrians, and the one thing that can
make an Oresrian deadly is being confused the way you've just confused them, with their deadly
enemies the Thargoids. Check the thorax markings and the shape of the fourth joint on each hind
leg before you jump to conclusions again . . .'
Alex followed McGreavy gratefully, away from the whispering insects."