I think your circuit needs a resistor between +5V and output. Then (and only then), this represents some form of diode logic circuit. In the first circuit (if a resistor is inserted between +5V and out), and assuming a volt drop of 0,7 volts per diode, the two diodes with +5V inputs will not be biassed at all and will have no effect, however, the two diodes with the -5V inputs will be forward biased. The output will then be 0,7V higher than the -5V, i.e. -4,3V.