Then use WinRAR.

For the rest of us, this is expected behaviour, and I don't want 7z special-casing exes or always extracting all files in an archive just to open one.

It could always be a setting. Feels like yet another situation where OSS prioritises principles over usability/practicality/reality.

If I want to open the README in a multi-gigabyte archive, why would I expect to extract all of it, even as a setting?

This seems the expected and reasonable behavior to me, as a second data point.

Because of the behaviour I detailed in my initial post? Wouldn't apply to ReadMe's though, it doesn't have to be that dumb. At least one other poster agrees with me in the comments too.

Aren't all extension special cased anyway?

Definitely sounds like 7zip takes security more seriously -- I would definitely want my archiving software to only handle archiving, not starting programs for me.

Yes! This has been a major annoyance with 7zip - and not only it doesn't extract all files (this isn't just for EXE files but a lot of files tend to have dependencies on other files - like HTML files depending on images or other HTML files) but it also has a race condition where 7zip and whichever program is associated with the extension of the file you're trying to open race to see if 7zip will delete the "temporary" file first or the program will open the file before 7zip manages to delete it.

7zip is good for extracting archives somewhere and for supporting a ton of archive formats (and especially for supporting disk image formats!) but as an archiving tool its features are barely barebones.

Which is basically why on Windows i tend to have both installed - WinRAR for being an actually good (and very fast) archiving tool and 7zip for handling the archives WinRAR cannot handle.

(though nowadays i handle most archives via Total Commander - which i use even on Linux via Wine :-P - which asks you if you want to either extract just a single file or all files in the archive and is IMO the best approach anyway)