Trisquel should not be password-protecting GRUB by default. It's a mostly
useless security feature and causes confusion.
Everything else you experienced was probably inherited from upstream
(Ubuntu). Fedora uses a different installer (Anaconda as opposed to
Ubiquity), so that would be why Fedora detected Windows at the time of
installation but Trisquel did not.
I do kind of agree that Anaconda is better than Ubiquity these days. But
Canonical would be unlikely to switch to it, and it would be more effort than
it's worth for Trisquel to do so when it's so much easier to just use what
Ubuntu uses.
