Uh... yeah, we kind of knew. A lot of us knew we had a good chance, or at least a decent one.
There's actually a really, really big gap between saying "her acting this way was predictable because she would predictably feel insulted" and "she was right to act in the way we predicted."
I mean, Lord Vegeta, pre-Sealing, would predictably react to any 'backtalk' from his son by hitting the boy with a Big Bang Attack or something. He regarded such backtalk as "a direct slap in the face" and "an insult." That doesn't mean doing so was right by any stretch of the imagination.
Uh... then why does she have power, authority, or a right to act in the politics of the Exiles and the Saiyans? I mean, if Valentine Somerlad doesn't have a say (indirectly) in saiyan politics, where does Regent Dandeer's say in those politics come from? Her claim to political power comes entirely from the notion that she's been (indirectly) consulting her husband.
Alternatively, if Dandeer/Doreen's authority over Jaron comes from being his mother, then why doesn't Valentine have similar authority? Sealed or not, he's still part of a marriage, right? Does he not get a say in what happens to his own son? If so, that's a very unequal marriage.
[You could argue that Lord Vegeta has no right to any say in what happens to his kids, and you'd be right- but the entire point of the Sealing was to metaphysically amputate the parts of "Lord Vegeta's" mind that made him such an abusive evil fuck. If Dandeer, with full opportunity to do so, didn't forcibly MAKE Lord Vegeta into a good father, then that is a major failure on HER part given how much incentive she had to try and how long she's had to do it.]
Aaaand now you know why the Vegetans were right on the edge of openly revolting against Dandeer's regency! Because from their point of view, if we acknowledge this completely obvious truth, then Dandeer was basically a usurper who seized control of their government in a coup by mind-controlling the king and the prince.
The legal fiction that 'Lord Vegeta,' even when addressed in terms of metaphor and allusion, has authority over the Vegetans, is the only thing that kept their government from blowing up during a four-year regency.
Furthermore, if we're talking about who has the legal right to do what, that loops back to the point that while Valentine Somerlad doesn't know anything about saiyans, he DOES now know about ki and his son having ki powers, and the upcoming alien invasion. He has sufficient information to make a fairly well informed decision on whether his son can train to fight with ki.
To be fair, the "defeat a super saiyan" part happened when the super saiyans in question were asleep and badly wounded (probably not even transformed), respectively. The latter may not have happened at all since we have no idea if Dandeer told the truth about what passed between her and Jaffur on the night of Lord Vegeta's Sealing.
The one-on-two fight? Yeah, that was all Berra. Had Berra not intervened and had physical power that mismatched and ludicrously overmatched the Kakara-Jaffur teamup (as you'd expect a grown man to outmatch two eight year old children)... Dandeer would have lost that one hopelessly. She'd have been stranded away from the action while the Senzus caught up with us and whisked Jaffur away into safety.
Uh... what?
Now I think you're being... reflexively super pessimistic, excessively so.
To be fair, Dandeer is on thin enough political ice that her effective power is very limited, especially if it gets out that she reacted this way to us directly consulting "Lord Vegeta" on an issue where even Sealed he was in a position to understand the risks and issues involved now that the secret of ki is out.
There's risk of Dandeer breaking out heavy-duty magic against us, but by the same token if she starts launching magical attacks at us like that we DO have allies, and people who would intervene on our behalf. We do in fact have Seers watching our backs. And Berra, Yammar, and Apra all have their own separate reasons NOT to tolerate Dandeer tampering with the Scion of Goku, or Dandeer acting in ways that compromise the defenses of Garenhuld in the face of the alien threat.