I am a mutualist as well. I just use the term, economic democracy as David Ellerman calls it, instead because mutualism doesn't seem as clear. Also, mutualism has anarchist connotations, which I am sympathetic to, but I believe the movement to abolish capitalism should be broader than anarchism.
In other words,
anarchist economic democracy = mutualism
Marxism is not the only anti-capitalist critique. There are more modern non-Marxist critiques of capitalism such as the theory of inalienable rights. See: https://www.ellerman.org/inalienable-rights-part-i-the-basic-argument/
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