It seems that string data must be written in ASCII code. Thus, the following modification allows it to be read.
<DataArray type="String" Name="pointNames" NumberOfComponents="1" format="ascii">
112 111 105 110 116 78 97 109 101 48 49 0
112 111 105 110 116 78 97 109 101 48 50 0
112 111 105 110 116 78 97 109 101 48 51 0
</DataArray>