But it is an AND. Look at the truth table:
In1 In2 Out
0 0 0
0 1 0
1 0 0
1 1 1
Thus Wired AND - both inputs must be High for output to be High.
If Both needed to be High to make the output Low, that would be a NAND - if you were to take that output and invert it using a NPN collector follower,
In1 In2 Out
0 0 1
0 1 1
1 0 1
1 1 0
And there's Wired OR, with diodes flipped around - either input High makes outpt High:
In1 In2 Out
0 0 0
0 1 1
1 0 1
1 1 1
If you were that output and invert it using a NPN collector follower, then you have NOR:
In1 In2 Out
0 0 1
0 1 0
1 0 0
1 1 0
In all cases, the diode serve to isolate the inputs from each other.
If either but not both were to affect the output, that would be Exclsive OR, XOR:
In1 In2 Out
0 0 0
0 1 1
1 0 1
1 1 0
XOR/XNOR more difficult to pulloff with just diodes & resistors tho.
and inverted, XNOR
In1 In2 Out
0 0 1
0 1 0
1 0 0
1 1 1
Generally, Wired OR and Wired AND are all that's needed - if any of several inputs go low, the output goes low - such as with a keypad, pressing any key to Gnd can be used to create an interrupt and tell the code to go scan the keypad.
If you want action only with 1 or the other, that's easier to mimic in software - similar example, with multiple keys pressed, scan the inputs, if more than 1 was pressed, ignore the result.