It's not uncommon to discuss CCD cameras for large telescopes without making any mention of the focal length or aperture of the telescope. See, for example: https://www.eso.org/public/teles-instr/lasilla/ntt/susi2/
Here's a page for another imaging device which lists the aperture and f-number of the telescope—and then gives a separate f-number for the instrument, without stating the instrument's aperture: https://www.eso.org/sci/facilities/lasilla/instruments/wfi/o...
So I don't think the LSST media department dropped the ball on this one. The numbers (focal length and aperture), which you understandably think of as being essential info for any camera, just aren't as relevant here, partly because comparison with other options isn't in the forefront of the scientists minds (the camera is totally bespoke and there are many ways in which it is tailored to the telescope, which constrain its design, including in those two respects).
Focal length and aperture of the LSST camera aren't mentioned here, either https://www.lsst.org/about/camera
Aperture is talked about in the light collecting area of the mirror, and often summarized to its diameter. 8m class telescope, is a telescope with an approximately 8m diameter mirror.
Hubble is a little over 1m.
Other things matter way more for a telescope and are much more interesting.
- "Combined with its large aperture (and thus light-collecting ability), this will give it a spectacularly large etendue of 319 m²⋅degree².[6] This is more than three times the etendue of the largest-view existing telescopes, the Subaru Telescope with its Hyper Suprime Camera[36] and Pan-STARRS, and more than an order of magnitude better than most large telescopes.[37]"
https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory