I don't think it makes sense to characterize Haskell as "big" on this basis, because 1) it is trivial to define an operator in Haskell, so there's bound to be a lot of them and 2) even the "standard" operators typically have a simple definition (e.g. https://www.stackage.org/haddock/lts-12.9/base-4.11.1.0/src/...).
On the whole, I consider user-defined infix operators to be a huge mistake. While the few common ones are great, the ability for every single library creator to add their own infix operator turns into a mess in the long run.
Those are mostly library functions, not part of the language.
It doesn't seem any more reasonable to use them to declare Haskell a complex language than it would to have the existence of, say, a linear algebra library providing mathematical operators for Forth mean that Forth is a complex language.
Is the STL part of C++? Sure, it's a library, but it's a standard library - it should be there in every conforming implementation. Personally, I think of that as part of the language.
Is some vendor's RS232-port-handling library part of C++? I would say no.
In the same way, I think that Java's standard library is part of the language, and is in fact the strongest selling point of Java.
Those are part of the standard library rather than the language itself though. You can (and a lot of people do) define and use your own standard library instead (hmmm... maybe a rabbit hole of its own? Although it seems companies with legitimate business needs do this as well so who knows).
https://haskell-lang.org/tutorial/operators