only trust coins we compile ourselves that come from reputable repos.
If you don't read the code you compile it doesn't change a thing.
I do not read the code I compile, most people don't read the code they compile. Most people (me included) expect someone will do it. Scammers know all too well these facts.
Open source gives a false feeling of security. Openess is worth nothing if it is not checked.
That's why open source software is secure ONLY if it is popular. And no altcoin less than 3 months old is popular enough (and 3 month old is very optimistic);
I for one am just a code junkie so I always read the new commits from a coin and never dabble in a coin that doesnt fork one of the well known coins out there.. There are only a few reasons someone would want to launch a coin idea from its own repo and scams are usually the main focus. Because like you said, no one wants to read the code even if its right there infront of you, for good reason, its thousands of lines long.