Imagine you are in a spaceship approaching a new planet, Xarg. All you know about Xarg is that it contains two races, one friendly towards Earth people, the other antagonistic. One race is called the Lamonians. The other is called the Gataks. Which do you think is the friendly race?
Or transfer the example to parts of London. If you don’t know the city, which sounds the nicer place to visit? Pimlico or Wapping?
People whose mother-tongue is English usually choose the m/l names.
In real life it is always unwise to behave on the basis of sound symbolism. As the Lamonians charge at you with ray-guns, it is no use shouting, “But your consonants say you’re friendly!” ( )