"the implementers have tended to appropriate Lispy syntax"
But doesn't it make sense that, once you're extending a Lisp dialect to add some Prolog implementation, you'll keep using the Lisp syntax?
I don't see it a question of lazyness or love: one of the main point so many people accept to deal with Lisp's seemingly crazy parentheses is homoiconicity.
It's not that parentheses are that great and that we love seeing: ))))))))) or )))]))]))) (in Clojure).
It's that the benefit (homoiconicity) far outweight the cost of using that syntax.
This might also just be laziness, or perhaps simply love for lisp syntax by people using lisp.