This is not the same as: "Unsafe at any speed", by Ralph Nader :-) I haven't read that book myself, but his subject was American cars, not chess openings. So it really does not belong to a chess site.
General drawbacks for each black opening?
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I'll limit myself to responses to 1.e4:
1.e4 c5 -> memory strain due to immense amounts of theory. Great stuff for people who have lots of time and energy to prepare, difficult to use otherwise.
1.e4 e5 -> a lot of second-rate lines for White leading to the early dissolution of the center or to symmetrical positions - in both cases pieces are exchanged too quickly to my taste. This is OK if You are endgame expert or willing to accept early draw from time to time. Still it is my choice in the last couple of years.
1.e4 c6 -> basically this is three openings in one (Classical, Advanced and Panov). Classical with 4...Bf5 is every bit as theoretical and as sharp as Najdorf Sicilian if Black castles kingside. Can lead to many minor piece exchanges. Advanced feels unnatural for both sides, but White has a lot of pressure. Panov is OK if You know how to play either Nimzo-Indian of Grunfeld, otherwhise You land in unfamiliar positions.
1.e4 e6 -> I would actually give it a go if exchange variation had been illegal!
Pirc/Modern -> difficult to use on a regular basis, White has just too many plans. Counterintuitive - in some lines You must avoif either ...Bg7 or ...Nf6 to be ready for Bh6 threat.
Philidor -> OKish via 1...d6 move order, terrible if You start with 1...e5. Starts to be unpleasant if You compare it to Breyer defense to Ruy Lopez.
About the old indian, by "safe" I generally meant both things: is the line playable for black or does white have a trick to tear it down? And also, does black have a problem with king vulnerability or his drawback in that opening is on other things like being behind development, middle, etc...?
"... Fine wrote his book prior to the post-war emergence of the Soviet School of Chess. ... Ideas Behind the Chess Openings is seriously out of date. Chess is a far different game than it was in 1943. ..." - Bill Kelleher (2002)
https://web.archive.org/web/20140708112658/http://www.chesscafe.com/text/review315.pdf
Perhaps the closest thing to a modern IBtCO is Fundamental Chess Openings by Paul van der Sterren (2009). It is pretty long, though.
https://web.archive.org/web/20140626173432/http://www.chesscafe.com/text/hansen128.pdf
Thats why i prefer the Latvian Gambit...no drawbacks, simply perfect 
Well it depends on what Klavierstucke7 definition of unsafe is.
He could be talking about King safety or maybe even asking if the line is safe to play. You never know. I guess we will have to wait and see.
If he is talking about King Safety. I believe the black king is completely safe on d8 after the queen trade variation.
However, normally white does not play it that often. I believe it is considered good for black for such an exchange. However, it could be tricky.