I started just closing the tab if a site thinks I want to signup before reading the content.
If sites are do desperate for the quick fix, I do not expect them to have good content below that modal dialog.
1) Subscribe "abuse@(sitedomain)" to the newsletter. I don't know if anyone still uses that convention but it reduces my frustration.
2) Add the site to my ad blocker blacklist so I don't waste my time by visiting again.