No, there are more asians by percentage in tech companies than asians by percentage of the general population.
If asians count for diversity, there is no lack of diversity of tech companies. If asians don't count for diversity, then the author's point is invalid since it shouldn't matter to morale whether or not the fired person was white or asian.
If asians count for diversity, there is no lack of diversity of tech companies.
This statement doesn't really make sense. By definition, no one group (or two for that matter) can "count for diversity", as "diversity" is the absence of such clustering.
The article implies that the lack of diversity, coupled with the fact that the CTO who is leaving could lower employee morale.
I don't know how else to parse that statement. If absence of such clustering is the meaning of "diversity", why would the departure of an ethnic CTO cause lowered morale?