It occurs to me that if you were to call the behaviour of pedophiles who prey on young men "Toxic Homosexuality", that would be seen as anti-gay and bigoted. So does that same logic apply to "Toxic Masculinity" for speaking of men behaving in a toxic way?
If you allow that term, you must then also allow the term toxic feminism. Watch the left roll around on the floor now. And the real horror is the pedophiles aren't just men.
Using the term 'toxic' when referring to behavior is not sexist so long as it applies to both male and female behavior. There is absolutely toxic femininity or feminism, so I don't see the issue as sexist.
It just describes how masculinity can bring out the bad in people. I don't see how it's sexist, or how pedophilia is "toxic homosexuality". It's a bad comparison in the first place.
What "masculine" behaviours are not "toxic"? I think you will find the people saying "toxic masculinity" would say any behaviours not toxic are either gender neutral or feminine. And I think they would scream misogyny were you to declare anything to be toxic femininity. It is straight up sexist.