We all rely on the clues like is the distributor well known, is the software very interesting to attackers, etc. Piping curl of random url to shell and running

We all rely on the clues like is the distributor well known, is the software very interesting to attackers, etc. Piping curl of random url to shell and running configure and make of tarball from random url is dangerous, because you do not know what gets executed. I don't see a difference, it's the same problem. If you have to run those programs, the safest way is to do so on a dedicated "untrusted" computer that has as little access to your data as possible. On your main work machine, rely on vetted software from well known reliable sources, for example your OS distributor.