I already pre-empted that: readability tracks what you learned first and how much you've practiced, and you trying to restate the familiarity effect as if it refutes it. You're measuring familiarity, not intrinsic readability. If you ask people about less popular language, say Haskell, yeah, they'd complain about its "readability" too.
> most common complaints against Lisps
Well, they are wrong on the other side of the fence. There are thousands of Lispers who'd say exactly the opposite, that: "Lisp is by far more readable than anything else"
You're cherry picking some fictive example about syntax, well, it's not a convincing one, comparing more than just a and b, blows up quickly, innit? `a === b && b === c && c === d`, while in Lisp it remains uniform `(= a b c d)`.
Lisp just uses one rule everywhere. "One uniform rule" vs "prefix for functions, infix for some operators, with a precedence table". You ever thought about that? You think you're getting an aesthetic point for binary operator example, while disregarding a bunch of layers that scream "simplicity".
> is the same cop-out Ruby programmers use
It's not the same, you clearly speaking as someone without honest, heartfelt attempt to use any modern Lisp dialects, like Clojure, Fennel or Jank. Honestly, try using Clojure, (re)write some personal shell scripts in babashka. It's truly great, and I'm saying that as someone who has used different languages, varied in paradigms. Interactive eval is not a substitute for static checking and I never offered such stance. Not to mention the enormous amount of research and experimentation on type systems that's been done by Lisp communities.