Even if the FA grabs the cup by the bottom to serve you, I'm sure the plastic cups came packaged in a sleeve. An FA may have touched the lip of the cups when separating them in the galley.

For glassware, most glasses appear to be stacked in egg carton-like crates where the FA would have to grab the glass near the top to pull them out (unless the glasses are put in the crate upside down).

Either way, I'm not bothered by the FAs briefly touching the lip. Most are pretty obsessive with hand sanitizer.