What principles are these?

I think there is Clojure and cloJure. The language is very different if you can mostly get by writing pure Clojure code, and another language altogether if you need to interop with Java constantly.

If you can get by mostly writing Clojure code (either by wrapping the Java libraries that you will use on helpers, or by using third-party libraries), it is a great language, even if in the end it is a very different from any other Lisp (but I'd argue that the changes are for the better, for example first instead of car, thread macros, protocols, immutable data structures). But yeah, for sure Clojure is much more optionated than any other Lisp.

Now, if you need to interop with Java code constantly, yeah, Clojure can be a pain. A good chunk of the code you will write goes to appease the alien structure that is the concept of Class on a FP language.

Which of Lisp's philosophies and principles does Clojure violate?

There it is again. Care to name any of those timeless philosophies without resorting to the minutiae of cons cells?

Clojure has very tangible and definite downsides and tradfeoffs (to name some: weaker REPL, though not as weak as some Schemes. JVM required. Heavy interop reliance), but it has served well as the flagship functional lisp.

Does XLST count then?