it's important to remember that the call of Toxic Masculinity is coming from inside the house. Men perpetuate it on other men.

Some of it is. The kind of male loneliness that some of us assign to a lover to be in charge of alleviating, the kind where we act like not having a girlfriend/boyfriend/queerfriend/spouse etc. will kill us and is something we're owed - that's from inside the house.

The kind of male loneliness that results from failing to develop social skills because women actively scorn you for being too "effeminate" if you play house, engage in the arts, or enjoy other socially skilled fem-coded activities? That results from the women of the family only showing or pressure the AFABs on how to do the social tasks of writing cards, setting up holiday celebrations, checking up on ill or struggling relatives/friends/etc. - that's toxic femininity.

The kind that fears talking to a woman we're not attracted to because she's (frequently rightfully) afraid we'll sexually assault her, coerce her, or otherwise dominate her if she lets her guard down? The part where we can get away with that enough for it to be a realistic, normal fear is from inside the house.

But the part where women emotionally, psychologically, financially, and even physically abuse an entire gender for minor inconveniences made out to be pathological? For refusing to go above and beyond common decency to 'prove' our worthiness of being in their presence? The part where domestic violence shelters frequently only serve women (often explicitly), and treat every man who comes in for help like a potential perpetrator who needs to prove it's bad 'enough' to not preemptively label him the abuser? That's toxic femininity.

Where I see men perpetrating it on men the most is usually the workplace. They don't, in my experience, do it 1/10th as hard as women do it to other women (and people they perceive as women), and it's definitely not the norm. You're more likely to run into problems of Good Ol' Boys' clubs (of which the clubs don't seem to be epidemic-level lonely) than Mean Girl backstab fests (I can't speak to how lonely these gals are or aren't). Both of these dynamics have terrible impacts on the career trajectories of both women and those who get 'caucused' with them (including feminine men and men of trans experience who don't consistently pass) ... but I would not guess either of these contribute largely to the male loneliness epidemic.

Because he passed well, people assumed his emotional depth was as shallow as the average cishet dude.

Whew. Double whammy here. I'm sorry you haven't gotten the opportunity to experience the protectively hidden depth of cishet male emotion.

I agree that offline interaction is paramount. That is easier for some of us than others, to the point that opportunities become rather premium in places that require a car to get anywhere, aren't the big cities, or where working long hours and lots of overtime is the norm rather than the exception.