You want me to educate you in basic history?
I hereby reject everything you referred to, on grounds that all cited source material comes either from Slavs or British/American historians, whose countries fought against Germany. Therefore it is not possible in the slightest that what they say is neutral or unbiased.

See, this game can be played in both ways.
About why many Slavs fought on German side, RRW and Corsair already answered.
Yes. Inconsistent Soviet propaganda and earlier alliance with Nazi Germany, alongside with the fact that they "understandably were desperate and hateful of Stalin enough to fight with Wehrmacht". And the fact that nobody was killing and Germanizing them. These explanations are acceptable.
Yes, if you were occupied, why didn't you resisted? Like Finland in the same year. BTW, our "best friends" Germans supplied them with weapons.
Because we were, strikingly, simple-minded enough to hope that USSR would actually honor its agreements at least until ink has dried on them? You do know that it was not until we had agreed to sign a pact of
mutual assistance and non-aggression and allowed over one hundred thousand of Soviet soldiers across the border, that you pulled your little coup d'etat? Finland was smart enough not to do such a mistake. Not to mention they were still over 3 times larger than Estonia, population-wise.
Now, would you please answer just two simple questions:
1) Try and predict progress and result of following military confrontation:
Defender: Estonia.
Population: ~1,136,000
Armed forces: ~15,000 men total in all categories, plus civil guard of 36,000 men and 14,000 women.
Has declared neutrality and is thus not part of any military alliance. (Except with Latvia?)
Attacker: USSR.
Population:~170,000,000
Armed forces: ~1,800,000 ground forces alone (1939 data, as much as 3,000,000 in 1941), of those ~100,000 already stationed in Estonia, several times as many right across the border. Never mind full aerial and naval superiority.
Is allied with Nazi Germany.
If the task is too difficult, feel free to consult military experts of your liking.
2) If I take your family hostage at the gunpoint, then ask for your wallet and you give it to me without resistance, does that mean I become its rightful owner and you are not justified to take it back later nor take any legal action? Simple yes or no please.