It should be attacked three times. The melody and chords are clearly two distinct voices. Actually, I can't think of a context in piano music where you wouldn't attack a harmonic unison on two different beats as notated (unless there was a tie written in, of course).
In contrast to some of the other answers, I don't consider this to be sloppy notation. If this is indeed what the arranger desires, then writing half notes in the left hand chords keeps the rhythmic pattern visually consistent, while this right hand notation conveys the cohesion of the melody.
In theory, you could write in quarter rests to resolve the "ambiguity" of having to play a note that is already ringing, but I consider this a solution to a problem that doesn't exist—there is no ambiguity to begin with. Moreover, if I saw a rest on LH beat 3 of measure 4 but not in the same place in measure 3, I might assume they are to be articulated differently.
The notation is fine, but is it sloppy writing? I don't think so. In piano music, overlapping or crossed voices are common enough that everyone has to learn to play them at some point. You will find many examples in Bach. And in the 21st century, there's no expectation that you are even playing both lines on the same physical keyboard: You could be using one patch for the left hand and another for the right.
Finally, it's worth mentioning that many pianists will reflexively play a passage like this with pedal, in which case you don't have to use your finger to hold down the long notes and playing them again presents no problem.