I can confirm this with the latest vim-nightly.
your vimrc loads first (where you have defined your highlighing)
then syntax/synload.vim does override it with:
" Set the default highlighting colors. Use a color scheme if specified.
exe "colors " . colors_name
where syntax/syncolor.vim ...
Ok, so I have a prototype of a license concealer (not fold) written, but I think because of the way conceal and cchar work, I can't get the lines to collapse into one. For that, folding may be better.
A quick example, that doesn't work with comments (yet):
let text =<< trim END
Copyright (c) 2016 David Ben Knoble
Permission is hereby ...
My answer is very similar to Martin Tournoij (full credit to him).
This just makes it in a single-line command. When you run this, it will disable continuation of comment permanently:
echo 'au FileType * set fo-=c fo-=r fo-=o' >> ~/.vimrc