This was all understandable. The growing issue made Florentia move quickly. They had already sent people to Dubois' mansion and said they would investigate. Florentia was trying to assert their position as a faction who protects humans. Florentia received a lot of funding and assistance from humans and didn't want to lose it.
But Valerie heard— Jasper wasn't ready to accept any Florentian delegation to discuss the issue. Jasper hadn't even contacted Valerie at all. But the general understood why Jasper said he wanted to leave Florentia.
There was no punishment in Avalon against vampires who prey on humans to death. They would only be punished if a conflict arises. For example if they prey on important human figures such as village heads or officials. Or if there were humans who were preyed upon without going through the procedure.