A lot of the discussion about 'poaching' depends entirely on our own definitions of what it means, but poaching to me has always been one entity stealing a participant from another entity while a contract was still active.
I think what a lot of people tend to ignore in regards to Kson and Nazuna is that:
A) Kson and Mikeneko are Indies and were therefore not poached from anyone.
B) Coco and Rushia did not have the option to remain at Hololive open to them as one was terminated and the other was effectively squeezed out.
Similarly, letting your contract run out like Moruru (Luna), being effectively axed like Nobuhime (Polka), or graduating due to a family situation and then subsequently joining a smaller company a year later (Tomoshika) probably doesn't qualify.
The only person I would reasonably describe as 'poached' would be yoinking Rosemi only a couple weeks after joining Tsunderia, but even then it's not like Nijisanji went to her directly, they just accepted her into Obsydia and gave her the decision on her career path. Komori Met to VSPO could also be considered poaching but eh...she's been a solo talent under 774 for a while so her connection to VSPO and subsequent move felt very organic.