App Store is about central authority. F-Droid is about freedom to add whatever repositories you deem useful. It's up to operators of F-Droid-the-repository to decide what they want to host. But it's up to you to add another repository to the list. You say there's no other repository hosting Gab? That is not a problem that can't be dealt with. Unless network operator decide to ban routes, it's just a work (setting up a repository and trust) that needs to be done.

EDIT: This is mentality I find hilarious. It's either I can something for free or I can't get it at all. I think freedom in this case is about having something with little expended work.

This is mostly untrue.

There was no requirement to blacklist gab. Mastodon clients on f-droid are allowed let users use Gab.

What f-droid does not allow is apps preconfigured to connect to Gab, or who's primary purpose is to connect to Gab.

There was even a petition to have fdroid remove an app (fedilab) that had a blacklist to disallow Gab then removed it, claiming that removing Gab from the blacklist was specifically endorsing it, and there were some people who tried to claiming that not apps that were not blacklisting Gab when other apps did meant those apps primary purpose was to connect to Gab, but f-droid weren't having it: https://gitlab.com/fdroid/fdroiddata/-/issues/1736.

However, they did consider an app that was a straight fork tracking another with the only change being the removal of a blacklist to be disallowed.

F-Droid is both a client and a repository. The official F-Droid repository has policies that were clarified in other replies, but it's also important to note that you can add arbitrary repositories and manage software from them with the F-Droid app.

The "build your own if you don't like it" answer is often absurdly impractical, but not here. Someone who feels it's important can put up an alternate repo containing clients preconfigured to connect to Gab and even an alternate build of F-Droid preconfigured to use it in an afternoon.