Paying for a mod is just silly, but all freedom to anyone that wants to pay someone to make them a mod. Charging for mods is just silly too (especially on a ten year old game). Separate work and play, and get a real job. Modding is for fun not for funds! But still if you want to charge for a mod then all freedom to you too. What is unethical however is taking advantage of the language barrier of many Ukranian Star Wars fans and giving them a subscription-based mod with copied content from original content authors just because they didn't know that Jedi Academy can be played with all these content mods for free.
I myself would never charge to make mods for someone, but if a person really wanted to thank me for my effort after I complete their mod and without prior arrangements then they could donate if they wanted. I do charge people that want websites (cheap though!) because it really takes a big chunk of my time to develop it in-between university work and other projects.
This is one of the reasons I stopped working on Jedi Knight Galaxies. The "project leader" got his money from the Donate button to "cover expenses" for the website of a mod that was far from release state. The original project leader barely lifted a finger to contribute to the development of the mod, apart from being the "ideas guy" and sometimes opening photoshop and making some HUD graphics. The mod itself was broken, the team structure was broken, communication didn't exist, the project was failing. But PR was still pouring out optimistic "news" to keep the fans clinging on. Much of the content shown was heavily prototyped garbage or fakery that was made specifically for the dev diaries but had little significance to do with the gameplay of the mod itself (The horrible untested broken running animation even passed through to release). A large bulk of time in the development of the mod was spent making a fully-working fully-animated stargate system that allowed the developers of the mod to travel between servers instead of using the /connect command. I feel really sorry for people who clicked that Donate button and hoped something playable would come out of the project in good time.