How safe is it to use PayPal really?

For a very well established entity, I have to say you don't do your due diligence as one would expect from such a "well established" institution.

How can we as consumers trust your company with our transfers when you don't even do a background check on companies that's using your services? I mean I didn't have to do much research on a company called Adoncast digital to find out that they are a bunch of *******. How did your company not flag them? Why are they not blacklisted from your data base?