For many, many reasons, Zhen Liu was rather justified in wanting to just mercy kill all of Dante's wild kaijin spirits.
Every single last one of Dante's Kaijin were designed explicitly to cause suffering and pain, not just to others, but on themselves as well
Dante didn't just infuse [Cores] into aether beasts for shits and giggles, he did it because of two reasons.
First, he couldn't do what Zhen Liu could do to create kaijin. Because he wasn't a true Kaijin Lord, Dante could only twist and distort things that were already ablle to fight on their own.
In other word, between a baby and a broadsword, Dante would go for the baby and turn it into a Kaijin.
Second, and this was the more relevant reason, Dante did so in order to have the pain and suffering of the original aether beasts fuel their new kaijin forms.
