This just doesn't include enough context. Clearly the existence and popularity of the phrase in contrast with the absence of "toxic femininity" points towards what the parent was referring to.

Additionally, the central claim of toxic masculinity is basically that certain aspects of masculinity are universally toxic, which is really the only reason for such a term to exist. Aspects of most things are sometimes toxic, and thus don't deserve their own term.

IMO, the level of general acceptance that the concept of toxic masculinity has is mostly a product of the moral high ground that it's proponents currently hold in the culture and not because of serious intellectual underpinnings. The whole thing requires very specific framing that seems to have been constructed by starting with the conclusion and working backwards from there.

Do you think it's somehow not "universally toxic" to be inculcated into the notion that the only legitimate (as in socially sanctioned) forms of emotional expression available to you are lust and rage?

And then to be told those are "bad" too?

That's absolutely universally toxic to men's mental health, unless you can suggest to me a circumstance in which that's healthy, correct, and appropriate?

Regardless, that's a straw-man notion of the term. Healthy aspects of a thing, over-valued or under-corrected, can become unhealthy, too.

For example, "Boys will be boys." There's a legitimate idea behind that phrase: we want to encourage boys to be risk-taking and adventurous. It's also used to excuse a lot of shitty behavior, which teaches boys that (their) shitty behavior is tolerated.

Please tell me how that's not inherently toxic.

EDIT: And maybe you're just talking to the wrong people; the folks I talk about these things with absolutely talk about toxic femininity.

Personally I don't think your example is even an issue, even in a much more restrictive time men openly had a much broader range of emotions than that. But regardless, if toxic masculinity had such a narrow scope then sure, there'd be no point in arguing about it at all. But it's not, it's a heavily politicized term which is often used to attack masculinity in general, or any aspect of it that happens to be convenient at the time. A lot of the value it might have had as a term has been taken away by how it's ultimately been used. It's largely boiled down to a sort of slur.

But in regards to your edit, yes it's very possible that we're just talking to very different groups of people. I have to admit that I typically interact with people who either have no interest in this at all or who are taking it too far and are overly zealous. And of course, I'm not going to get a great picture of things as a casual observer on the internet either since that tends to bring out the worst in people.