> I think you and people with similar points are exaggerating
I hardly think I am exaggerating by stating this concern. The development of one-time use cups (like dixie cups) was primarily to address sanitary issues. I can see lipstick on a glass, I can't see funky residue inside a straw.
I've discussed issues with soap use at some cafes that use reusable ceramics (as it can leave a residue and affect the flavor). One owner of a higher end cafe told me that they chose rather to sanitize their cups with a high temperature commercial dishwasher. This violates their local health code but is practically acceptable.
Anyways, I know it's possible to disinfect straws, but if it proves to be more complicated or requires a lesser known process (like boiling them), the odds if it not being done properly or not at all go up.