I'm sure there's nothing wrong with the program at all =)
Modern webapp deployment approach is typically to have an automated continuous build and deployment pipeline triggered from source control, which deploys into a staging environment for testing, and then promotes the same precise tested artifacts to production. Probably all in the cloud too.
Compared to that, manually FTPing the files up to the server seems ridiculously antiquated, to the extent that newbies in the biz can't even believe we ever did it that way. But it's genuinely what we were all doing not so long ago.
Sure, but having a hands-off pipeline for it which runs automatically is where the value is at.
Means that there's predictability and control in what is being done, and once the pipeline is built it's as easy as a single button press to release.
How many times when doing it manually have you been like "Oh shit, I just FTPd the WRONG STUFF up to production!" - I know I have. Or even worse you do that and don't notice you did it.
But it's genuinely what we were all doing not so long ago
Jokes on you, my first job was editing files directly in production. It was for a webapp written in Classic ASP. To add a new feature, you made a copy of the current version of the page (eg index2_new.asp became index2_new_v2.asp) and developed your feature there by hitting the live page with your web browser.
When you were ready to deploy, you modified all the other pages to link to your new page
It's good practice to run the deployment pipeline on a different server from the application host(s) so that the deployment instances can be kept private, unlike the public app hosts, and therefore can be better protected from external bad actors. It is also good practice because this separation of concerns means the deployment pipeline survives even if the app servers need to be torn down and reprovisioned.
Of course you will need some kind of agent running on the app servers to be able to receive the files, but that might be as simple as an SSH session for file transfer.
Shitty companies did it like that back then - and shitty companies still don't properly utilize what easy tools they have available for controlled deployment nowayads. So nothing really changed, just that the amount of people (and with that, amount of morons) skyrocketed.
I had automated builds out of CVS with deployment to staging, and option to deploy to production after tests over 15 years ago.
Except that FileZilla does come with bundled adware from their sponsors and they do want you to pay for the pro version. It probably is the shittiest GPL-licensed piece of software I can think of.
Of course, it's going to be difficult to find a modern application where each individually deployed component isn't at least 7MB of compiled source (and 50-200MB of container), compared to this single 7MB war that contained everything.