That's a great point, and I'm definitely interested and in favour of readability.
How about this, though: I know that Tor doesn't want to be in the business of site reputation, but what if (eg) Protonmail offers a Onion "Safe Browsing" extension some day, of known-bad Onions for malware reasons?
There's quite a gulf between stripping hyphens from a candidate onion address and doing strcmp(), versus either drilling into the candidate address to compute the alternative forms to check against the blacklist, or even requiring the blacklist to be 8x larger?
-a