This has nothing to do with Akeeba Backup and everything to do with how the operating system of the web server works. Please read the entire section
How your web server works in our documentation. Since your web server runs under a specific user all of the files written by PHP scripts on your server are owned by that user. We can obviously NOT do anything about it because changing the ownership of files requires root privileges (hence the need run
sudo chown as you pointed out). Do remember that this is how your web server's operating system is designed to work.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!