You get some men who seem to think a mention of toxic masculinity is an attack on men. It's not. It's largely identified as something which is detrimental to men.
Things like the idea that men shouldn't convey, or even feel, certain emotions. That they should be strong, financial providers, good at fighting, having lots of sex, etc. Very few men are actually capable in the all the areas that society tells them they need to be. It leads to poor mental health and a lack of willingness to talk about their issues. That is toxic masculinity.
It's worth noting that toxic masculinity isn't something that comes exclusively from men. It's produced by society at large and women are just as guilty of perpetuating it as men are.