Collapse (badly/modern) cited mail thread in gnus?

When I get an email from someone using outlook or whatever, Fastmail shows their top-posted reply followed by a clickable (...) which expands to show the full cited mail thread with lots of details and unrelated derailings and arguments and passwords and stuff I'm generally not interested in. Gnus, however, just shows it all, making it hard to see what was new in this email. Has anyone got a solution for this already? (I know about gnus-treat-hide-citation but it doesn't seem to work with most html mails.)