Earlier quoted context omitted.
No one is saying that mobile readers shouldn't ever share a URL on the "m." subdomain (despite them, quite literally, saying that). The criticism is that Wikipedia even has 2 separate resources for the same article and that the default behavior on "m." is to share the mobile resource while that's not the same case for the "en." subdomain (or other language variants). The only thing being said is that it should be con…
I agree with criticism of Wikipedia’s behavior. I disagree that ordinary visitors to the website should need to or indeed should manually manipulate the URL of the page they’re on in order to share it with someone else. If you’re sharing the URL directly with a specific person who you know feels strongly about which URL they received, then sure, do it to be nice. But I disagree with prescribing that one URL should be…
Everyone agrees with you on this point. You shouldn't need to manually manipulate anything but, because Wikipedia keeps a desktop resource and a mobile resource, there is a distinction and so you do need to manually manipulate it if you're sending a link from mobile to someone else and don't know their device. That doesn't change the fact that sending a mobile URL should always show the mobile page because that is, in fact, a unique resource and, therefore, has a unique URL.