I'm not an art critic, but my understanding this is in parallel with the memorial to the murdered jews of europe:

https://en.wikipedia.org/wiki/Memorial_to_the_Murdered_Jews_of_Europe

As the maze of blocks represents the fear, confusion and directionlessness of the jews in that dark time, so too does the concrete cube, and it's unassuming exterior, represents the way the gender diverse had to hide their identity, remain closeted, to avoid persecution. Only by getting close, can you see who they really were.

Art is most powerful when it's subtle. Art should not tell a story to the audience, but instead guide the audience in the direction of the conclusions they should make. It's not there to answer questions, but ask questions and challenge the audience to understand the answers.

Why have Mount Rushmore when you could just put up a big sign that says "Washington, Jefferson, Roosevelt and Lincoln were all good presidents."?

There's this permanent fixture now:

https://en.wikipedia.org/wiki/Memorial_to_Homosexuals_Persecuted_Under_Nazism

I think this, right in the middle of Berlin, is fitting and appropriate.

Minor correction sorry, you got it the wrong way around, cancer has Putin.