I think their theory is that the lion was brought to Constantinople by legitimate means, then looted _from_ there by Venice.
But they were also an anti-colonial struggle to liberate occupied native christians from the imperialist ambitions from the Arabian peninsula.
The political landscape of that time was truly complicated and chaotic in a way that is hard to truly capture in the image we have of that time period brought through general education, mostly because of lack of time to explain it all properly