This seems like a very muddled claim to me. I won't refute that there's some kernel of truth in there somewhere, but using anecdotal evidence to loosely tie one's own theory together rarely ends well, especially when one's claim would be beneficial to oneself if true.

A perhaps more plausible and/or stronger explanation for programmers' disproportional display of music talent as a group:

To gain the experience necessary to label oneself a programmer, one has likely a >lot< of time on a computer. Whether that computer exists at home or at a school/university, we can already likely assume (especially for the population of "professional" programmers, due to the lesser availability of this necessary resource in past decades and the length of time necessary to become a "professional") that the group we're talking about trends toward the higher income side of the population. That alone would make the group as a whole far more likely to have ever picked up a musical instrument in the first place, let alone to have received the countless hours of necessary instruction.

Additionally, I think we can all agree programmers are disproprotionally likely to be homebodies. If one spends a lot of time at home, one has more opportunities for practice.

Lastly, if one has the patience and determination necessary to learn enough programming to label oneself a programmer (especially a "professional"), then one is more likely than the rest of the population to have the same patience and determination necessary to learn another skill which requires countless hours of disciplined study-- like music.