https://www.bing.com/images/search?q=tank%20man%20china
(For those who don't see results, this is my screen grab of the above at 18:12 UTC : https://imgur.com/a/3tzPV49)
Also, "Tiananmen Square massacre" still returns some image results:
https://www.bing.com/images/search?q=Tiananmen+Square+massac...
Therefore, the tweak for "tank man" doesn't seem to make any sense since all the other phrases to get to the same sensitive topic are not suppressed.