The whole article is based on two premises:
* that the Great Firewall of China blocking all instances of 六四天安門 in website text is expected and normal,
* that leveraging that behavior in any way (see Hyrum's Law) is unexpected and abnormal.
If the government seeks to filter any and all websites containing a given string, why would the Tokyo University be guilty of discrimination just by adding that string to their website? They are not the actor performing the filtering. One can argue it's the government of China discriminating against Chinese people who want to access information abroad in general.