Where has Paradox stated this? Or is just what you are choosing to believe? Other releases with Stellaris DLC haven't been perfect, but none have been nearly as bad as 2.2 and Megacorp.
You can either choose to believe that the guys who made this game are beyond incompetent and blind and didn't realize all those bugs were there,
or you can choose to believe they released the update despite knowing it would take a couple more patches to iron out.
If you release software that you know has a lot of bugs and issues, but you intend on fixing those after/while receiving user feedback, it's called a beta.
Since this beta was accessible to everyone, it's an Open Beta.
It doesn't matter whether they brand it as such, it doesn't matter whether they state it, it wouldn't even matter if they were entirely incompetent and didn't know it themselves:
2.2 was an Open Beta.
(And this is a thing that occurs frequently with PDX games, not just Stellaris. And it's something I approve of, because it's Agile Software Developement. The only issue is new players being unaware of how the releases operate, and expecting a fully smoothed out release, because PDX isn't explicitely warning them, or doing the sensible thing of putting the releases on seperate Steam branches, THEN fixing them and THEN rolling them out to the main branch.)