Except "toxic masculinity" is a simple phrase that clearly and unambiguously describes a subset of masculinity as having the trait of toxicity, in the same way "red paint" doesn't refer to all paint, but a subset of paint that is red. If I describe a "toxic mushroom," do you think I'm claiming all mushrooms are toxic? No, it's obvious I'm making a distinction there between toxic and non-toxic mushrooms.
Yet even when the actual definition of toxic masculinity is pointed out to critics, they will often refuse to accept it and insist that it refers to all masculinity regardless of what anyone or any source says. They know what the real definition is, and they don't care.
The term or its framing isn't the problem, the problem is the consistent bad-faith interpretation of feminism and its arguments.