The Lemmy developers don't seem keen on writing that code to help people leave their instance, possibly bc they also administer the Lemmy.ml instance too and its a conflict of interest scenario, but I think rather that it is simply the case that the software is still in an advanced alpha / early beta stage of development. Many other features were simply a higher priority for them to want to work on. One day maybe they'll get to that though.

In the meantime, supposedly the ability to label content has already been added to the latest software release - v0.19.4. It will take some time to update various instances though - maybe half a year - and e.g. if you scroll to the bottom of your feed you'll see those UI and BE numbers for your own instance, Lemmy.World, are still at 0.19.3. As people upgrade, it would be good to label the most extremist instances like: "many people on these instances are often rude, condescending, and will spam your notifications for weeks after you indicate that you don't want replies anymore, and their admins refuse to do anything about it and sometimes even join in the fun"... or perhaps something more politely worded.:-P

With such a label, new users would not have to depend upon reaching any particular website that explains things - they could come here and start using the Fediverse directly, immediately:-). Another alternative that an instance admin mentioned is automatically blocking "those instances", but with a bot sending a new user information about how to remove the block, if they have a thicker skin and would like to engage. That would change everything, imho, bc it makes going to such a place consensual, which really does make a huge difference. If someone wants to get "dunked on", then by all means, enjoy! :-D

But it would protect people from wandering into "those places" without knowing. Which increases freedom for everyone across the entire Fediverse, especially since normal/average users may then be more comfortable to be on the Fediverse, and contribute their posts and comments and such:-). So I 100% get what you are saying - we need moar pictures of cute kittens, not fewer! But... it will take time. And in the meantime, this place is only for either those with a thick skin, and/or someone willing to put in the time and effort to learn how to use it i.e. to study the responses, identify where they come from, then block them to curate their overall experience - very much similar to needing to configure a Linux machine imho:-).