Piracy sites are breeding grounds for malicious software. The "Download" buttons on these sites are often disguised ads. Clicking them can trigger a download of:
Filmyzilla is not a charity. To make money, they run malicious ads.
When you download The Killer (budget: ~$30-40 million), the producers lose potential Indian streaming rights fees. If a film leaks on Filmyzilla, legitimate Hindi-dubbed distributors often cancel their deals.