Not only your opinion. It is fairly common among Forth enthousiasts to talk about “a Forth”, rather than “Forth”, as two Forths can be hugely different, yet be recognized as Forths (lisp is similar in that regard)

The ideal system is optimized for its problem domain. That means not only adding needed functionality, but also dropping unneeded functionality, and tweaking functionality to better fit the problem at hand. That’s not surprising for a system that shines when running with very little memory.

That’s different from, say C++. Nobody says clang, gcc and Visual C++ are “a C++”.

If they were philosophically similar to Forths and Lisps, those writing programs in them would be happy to change int promotion rules, operator precedence, vtable layout, etc, and different compilers would make different choices there.