In order to legitimately claim that a particular datum counts in favor of one theory over another, at least two things must be true: (1) The theory must lead us to expect the datum in question; and (2) The theory with which it is being compared must not give us reason to expect the datum in question. The reason for this is obvious enough: if the phenomena is equally likely on both theories, then it cannot (and does not) aid us in choosing between them.
We may grant, then, that evolution leads us to expect the datum in question (or at least, something sufficiently similar to it). However, this is not enough; the evolutionist must make the further claim that the creation of the world by an intelligent designer would not lead us to expect the datum. However, why shoud we think that? On what grounds could the evolutionist possibly detect what the intentions of an intelligent designer relative to the DNA of humans and chimpanzees would be, if there were one? Unless and until an plausible answer to this question is given, the argument cannot get off the ground.