Scams for quick cash.
Lesson here is don't buy a used phone unless you see it's unlocked or don't steal iPhones anymore. Their useless when the owner reports it missing.
Hell if you did buy it, suggest you don't bother buying used and just suck it up and buy new. Sucks I know but better than a scam and getting called a thief if your innocent. Most people that come here for this have bs excuses so excuse the bluntness.
There will never be a publicly released tool to bypass iCloud.
The point of iCloud activation is to stop phone theft... trying to bypass an antitheft mechanism makes you look like a thief, regardless of if you actually are or not.
This is why when people post these kinds of threads they are most often met with hostility.