You make it sound like the Caddy folks completely ignored the issue without providing a reason ("absolutely no reason", "doesn't even consider"). After looking into it, I find your post misleading and unfair, to say the
least.
Link to the issue for other users who, like me, were concerned by your post:
https://github.com/mholt/caddy/issues/1632
According to the author, the issue is that (a) there are two RFCs that contradict each other on this distinction, and (b) most browsers do not treat them as such for the purpose of their same-origin policies. So he thinks it's best not to enable this alternate URL by default since it's trivial to add it as another route if you want.
I don't know if he's right or wrong, nevertheless, this clearly isn't a dude that doesn't give a shit.