Hi
> It's not so much against the philosophy that against any SEO principle on this planet.
Well, I disagree, but that my be just differences in details of our understanding. After all, Google sees the URLs, not where they come from
I think we actually agree, that's exactly my point. If you build URLs based on menu items, then
the same article, piece of content, will have
2 or more URLs, one per menu item.
What sh404SEF enforces is that this can never happen because an article can only have one single URL, regardless of how many menu item are pointing to it. Remember, with Joomla SEF system, the same content will have different URLs based on the menu item used (unless you use "System links -> Alias" for the additional link, which maybe 10% of Joomla users know that it exists and what it's for).
> That URL should not depend on which menu items you clicked through to get to it.
Not necessarily. It should just be logical, unique and ideally contain keywords.
See above: if the URL depends on the menu, then there will be several URL for the same content.
Usually (I even think always, but not 100% sure), each of my pages have only one link, defined by the navigation
That's just you! and if it's not guaranteed by the system then it will happen (a lot) just by mistake or small problems, often in modules for instance (which do not properly search for the menu item associated for a piece of content and then just use the current Itemid).
So there's always only one menu path, i.e. a unique and logical URL to each page.
Again, that's just you, and it's good that you do that but it can only work for sites where a human being can grasp the entire site.
Also, and very importantly, if a module or plugin on your site generates links with a wrong or missing menu item,
you would never know about it. It may be that this happened on one or more of your sites, for years and you'd never know - because Joomla does not have a list of URLs on your site. Only search engines would know, and see all those duplicates. You could possibly track that with Google Search console for instance but most of times, you'd just do not know.
But if I go by category, what if an article or product belongs to several categories, which often happens. Depending on the component, there may be a way to set canonical categories, but not always. Which category do you use? How about tags?
If I go by menu path, I can choose to add the category to the path (same for tags), or not (mostly I would).
Not sure I follow you. You will have to insert categories in links and then you have duplicates. If the extension you use to have content in multiple categories does not have a way to insert a proper canonical, you cannot avoid duplicate content issues in that case, regardless on how you manage your links.
With tags, I'm not sure I see what the problem is: the link to the final article/product found on a tag page is not modified by the fact it' s on a tag page or elsewhere.
It just seems much more complicated to me, maybe just because I'm not used to that concept. Especially when working with components like AcyMailing that don't have categories for some pages.
Maybe it's about getting used to the concept, but basically there's no concept. A piece of conten is stored in a location (category hierarchy + title) and it's URL is always built based on that locatio, so that it never changes.
If the URL can change based on any cause (how you navigate to it in the case of Joomla) then you end up with multiple links going to the same content and we do not want that.
Best regards