Men don't have problems

Respectfully, most men in the men's rights movement are opposed to that term for a good reason. While there are some tradcons here and there, the men's rights movement is overwhelmingly progressive and against rigid gender norms.

Guilt, shame and lack of self-worth are two of the most salient factors leading to depression in men. It amounts to victim-blaming and is akin to telling men their place in society, shaming them for trying to fit into a narrow definition of what behavior is acceptable. 'Toxic masculinity' is not a diagnosable disorder. It is merely ideological drivel meant to derail conversations about mental health and detract from the true reasons of men's suffering.As phrases like 'male fragility', 'man up', 'male privilege', 'pussy', and 'grow some balls', TM uses shame and guilt as its vehicle to forcefully shape men's behavior and attitudes into something that the speaker deems more useful to their own goals.

The association with toxic and masculinity and by extension male makes me feel like something is inherently wrong with me. It feels like a constant reminder of all the negative stereotypes associated with people of the male gender. I do not think girls and women would be happy with a constant reminder of their "toxic femininity" either, especially when it is used with them in the context of being a victim. It is not about what they are trying to say, but the term itself. It reinforces rigid gender norms, and according to labeling theory acts as a self-fulfilling prophecy.

The term toxic masculinity contributes to the notion of male perpetrator-hood and by extension female victim-hood and thus directly plays into the Gamma Bias Hypothesis. For some tangential empirical evidence of the Gamma Bias hypothesis see Man up and take it: Gender bias in moral typecasting (the study is peer reviewed, this is simply a link to make it accessible to everyone; see also Tania Reynolds' YouTube video about the same topic). I believe it is a really, really harmful term that makes it hard for boys and men to see themselves as victims, and directly goes against the notion that boys and men should open up about their emotions.

Conversely, the same "toxic masculine traits" are often celebrated in women, an effect described by the Delta Bias Hypothesis.

The term also conceals the effect female sexual mate selection has on male behavior and the fact that mothers, not fathers show a "boys don't cry" bias; see Hypergamy¹ and Thomassin & Seddon (2019) – Implicit attitudes about gender and emotion are associated with mothers’ but not fathers’ emotion socialization (or the article summarizing the paper and articulating that even the authors expected to find the opposite).

¹ See this study that finds income is the primary factor that predicts a man getting married for evidence of female hypergamy.

For a more in-depth explanation of how male gender roles came to be and what purpose they serve, see my recent post "Toward a new theory of gender: an evolutionary take on the rigidity of the male gender role".