I uploaded a small patch for this called
Nameplate Tap Fix.
The purple color is set C side repeatedly onupdate and causes no trackable event as far as I can tell, so I just replace it onupdate. This is not extraordinarily efficient but it's not likely going to have any impact on your game.
edit: I should revise that, it could have an impact on your game if you had a
lot of nameplates on your screen, but so would any nameplate addon.
I think it could at least be reduced down to only checking enemy plates but I'm not sure what the best way to detect that is.