Why isn't a patch version allowed to narrow supported Julia versions?

just to note that it is an “automerge guideline”, not a rule of the General registry. The difference being you only need to follow it for your updates to be automatically accepted but they can still be manually accepted if the rule is not followed. So it’s not saying “this is how you must do it”, but rather “this is the most uncontroversial way to do it and so qualifies for merging without any further discussion”.