Maybe I am just misunderstanding the message, but I don't completely follow the logic on this decision. If it's to sympathize with the current societal issues going on, then I feel that they missed the mark. They have a powerful medium at their disposal through ARK, which could be used to resonate with people on these issues.
Think about if it would have been delayed, but with the intention changing from a celebration to a commemoration of the good intention of the protests, and the unity of races. Maybe there could have been unique dino colors offered during this time like they do for other events. I think a black and white monochrome color theme would have been pretty popular for breeding. If this happened it probably would be a completely different discussion we're having now.
The most disappointing part to me is that in the future when people look back at this games releases this will just be another delay out of a long list. It will not be distinguished from any of the other past delays, unless you knew what was going on.
I agree that right now probably isn't the time to be celebrating, but truth be told I don't believe that June 11th will be the right time to celebrate either. Does it really have to be a celebration though?