A lot of men don't like the term "toxic masculinity". Because it's an example of a potentially harmful psychological phenomenon called labelling theory.

Labeling theory posits that self-identity and the behavior of individuals may be determined or influenced by the terms used to describe or classify them.

The fact that we talk about toxic people and masculinity in the same breath makes people associate masculinity with toxicity.

I like to quote this source from an article published in The Palgrave handbook of male psychology and mental health.

There is a serious risk arising from using terms such as “toxic masculinity”. Unlike “male depression”, which helps identify a set of symptoms that can be alleviated with therapy, the term “toxic masculinity” has no clinical value. In fact it is an example of another cognitive distortion called labelling (Yurica et al. 2005). Negative labelling and terminology usually have a negative impact, including self-fulflling prophecies and alienation of the groups who are being labelled. We wouldn’t use the term “toxic” to describe any other human demographic. Such a term would be unthinkable with reference to age, disability, ethnicity or religion. The same principle of respect must surely apply to the male gender. It is likely therefore that developing a more realistic and positive narrative about masculinity in our culture will be a good thing for everyone.

Instead. A better term to use would be "harmful gender roles"