First, the uncontroversial: It leads to join-lemmy.org and some people might think that would mean donating to this instance. It should probably go to an on-instance page explaining different options to donate
Then, the can of worms: join-lemmy.org, AFAIK, is associated with lemmy.ml / lemmygrad.ml and, bluntly said, with those people being the tankies they are noone here can be quite sure that donations won’t end up supporting a genocide, end up in Kim Jong Un’s pockets, or suchlike.
Beehaw already removed it from their html (a bit hackish, but it’s the thought that counts)
I can’t know, but I can presume innocence. That’s not possible for people who openly support genocides.
Also, artillery isn’t bad as such. Speaking of: Those same tankies are also parotting the “Zelensky is a Nazi” line and are generally in favour of Russia’s invasion. I don’t mind weapons ending up in Ukraine as long as they’re in the hands of actual Ukrainians.