Comment by detaro

These cases generally are not about just someone that happened to sound the same, but someone who was choosen specifically and directed to sound like the imitated person. Even explicitly looking for similarity is generally fine, calls for voice actors will include references to well-known VAs as "the sort of thing we are looking for", only imitation is going to far.

(In music, some other cases have been about suspected misuse of actual recordings, e.g. a cover band being sued because the original musician believes they actually used one of their recordings, and disproving that can be tricky. I don't think that can as easily happen with look-alikes)