I think the point is not so much that the user is complaining, but the way the user is complaining. - Even more because it does not provide any helpful advice or idea.
So no, even as a professional you're not obliged to handle such users. As others already have pointed out. If you have a problem with a free software (or any free product), but can't provide any value, just do not communicate.
I disagree, as I mentioned elsewhere, the user made several helpful comments. It's not the users job to provide "ideas", that's for your product team (or you if you're alone).
It's the users job to explain the UX and problems with it. This user mentioned what, 5 or 6 different parts of the user experience that suck? And mentioned alternative user experiences that are superior.
I personally think the users email is raw and mean but still an extremely useful insight into the user experience with a lot of actionable stuff. I agree with the user. The programs settings, global overrides, styles, handling of user languages, etc are a nightmare for UX compared to modern products.
A good developer takes this email and empathizes with the UX problems, even if they won't redesign anything. A bad/petty developer gets snarky and mean and insults the user.
> A good developer takes this email and empathizes with the UX problems, even if they won't redesign anything. A bad/petty developer gets snarky and mean and insults the user.
Good developers aren't robots either. You get that kind of email, the best course of action is to delete it and move on.
If it's a large enough project you'll get the same feedback sooner or later from other users anyway, and that will be users with whom you can (and want to) communicate with.
So no, even as a professional you're not obliged to handle such users. As others already have pointed out. If you have a problem with a free software (or any free product), but can't provide any value, just do not communicate.