I'll do my best to address your points:
We are not going to update our UI because
We do not update UI without feedback from our community. The specific string "DON'T FORGET TO TAG THIS!" has now been changed. It must have been there for ages and as such, I presume a fair number of our members, myself included, have not been paying attention to the wording or the fact it stood in all caps. Thank you for the valuable feedback. The new wording reads "Your tags go here..."
Tagging doesn't really help and no one really uses it so don't bother
This is far from what I was saying. That said, perhaps your specific use case won't work here on fmsoup, leading you to make the above statement. Tagging is complex, the platform allows for it to be optional or to set minimums and maximums per category, while also allowing for some tags to be exclusive (like you saw with AI earlier). Generally speaking it is helpful in the sense that it adds context and that this can then be used by the platform and its users, this at very little cost to the authors who apply tags as they see appropriate. With this in mind, we encourage tagging. Tagging in the "Questions" category is optional, and tags are not curated. Will tags be useful for your specific use case? Difficult to tell. At this time, I do not see us removing tags from the platform. Use them if they work for you, skip them if they don't.
If you want an interesting weekly summary you have to manually tweak it
That's what preferences are for. They stand at the user level and belong there. No single notification setting will please everyone, nor can the system guess what you want to see land in your inbox.
Mac OS also has its default settings and has many preferences that users will customize. The defaults work for most users, but surely do not work for all. The software does come with constraints each user has to work with. People who are not willing to spend the time customizing their preferences have to deal with the defaults. We also have a budget that is considerably different than the one of Apple, but that is a different topic.
So if you have actionable feedback, we can look into things. If you want to voice how a given feature does not map well to your own workflow without being explicit about a possible fix, it makes things harder, but we can still have a discussion.
Concerning the Claris forums, as far as I know, the authentication mechanism is something that is not going away anytime soon. There are a number of english speaking forums about FileMaker, you can be on multiple forums at the same time if you wish, if you the kind of person to select only one forum, then pick the one with the best mix of community, feature set and any other criteria you may have. We rejoice about your contributions here on fmsoup and are glad to know that you are also getting help when looking for it. If there is anything else that can be done, feel free to message me directly.