I believe the intent was mostly understood by people online shortly after it happened, but now some excerpts from Connor Sturgeon's journal have apparently been released by police.
https://archive.li/PK1yF
Same article, other archive: https://web.archive.org/web/20231123024050/https://www.foxnews.com/us/louisville-bank-shooter-massacred-upper-class-white-people-highlight-lax-gun-laws-journal
Just select quotes here. More meat in the article.

The man who killed five people at a Louisville, Kentucky, bank in April was motivated by his outrage over the nation’s gun laws, which he considered lax and hoped a bloody rampage of white victims would spur politicians into action, according to a police report released Tuesday that contained excerpts from the killer’s journal.
[...]
"Perhaps this is the impact for change – upper class white people dying. I certainly would not have been able to do this were it more difficult to get a gun."
[...]
Sturgeon’s family has said they intend to sue the maker of the rifle used in the attack.