Is google that strict?

Because i saw many sites that has google adsense which are mostly warez site.

 

Warez is against the rules. They are strict, yes. If someone was to report those sites the publishers would probably get banned and would certainly get told to remove the ads.

 

They probably had a non warez site when they applied for adsense and then created warez sites with adsense on them. They are quite strict against these types of sites.