Something burning down is a tragedy, beyond anyone's control. It's also possible to love something for its beauty, and be sad that a globally historic monument suffered such an act of god that the irreplaceable art and craftsmanship is gone forever.

Something closing down, perhaps because there was not enough money to sustain its continued operation, when tens of thousands or hundreds of thousands of people were using it? That's a perfectly appropriate time to remind folks, "if you like free software, consider donating to help sustain the almost full-time effort it takes to keep packages like this alive."

Op said, "this is sad [because] I've been using this," and the implication is, "I want to keep using this but now I can't because it's gone" and making the connection that "one way to prevent this from happening to other packages you like is to contribute financially."