Nobody in Lisp does conscious paren matching. We rely on indentation. If you randomly deleted a parenthesis from some )))))), I would not notice. I would rely on the machine to tell me something is wrong.
Most "Lisp is unreadable" forum posting activity is just trolling by nonpractitioners. You can usually tell because it doesn't hit on the real readability issues, only the imaginary ones.
To read a Lisp dialect, you have to know what numerous words mean.
A seasoned Lisp coder cannot read the following, besides understanding its source code structure as data. I would guess that defcrunk foo defines something named foo, which is a crunk whatever that means. After that I have to be looking at the documentation of defcrunk (or asking AI).
(defcrunk foo (splat zing)
(:crom jang)
(:flit (burch culd)))
I suspect that a good proportion of Lisp is like this for newcomers.
Sometimes people make new Lisp dialects because they don't like the words and they want to make up their own. It might not be their main reason but it figures in there. Someone else has to learn those, including people that already know an existing Lisp or two.
Also, my above defcrunk thing will parse in many a Lisp dialect; and I could make a macro to make it work in some way. Trolls about Lisp have really latched on to this one. Their leader, a front end web developer, wrote a little article about it about an imaginary curse ...