In my side-gig pp I see about 12 clients/week -- most of them men; for my most recent 23 billed hours, 20 of them were with men. I am fortunate to live in a very diverse part of the country so the men I see (while all college educated and between ~18-35) represent various sexualities, relationship statuses, nationalities, and US ethnic groups. Given all that, intimacy is a primary concern for all but 1 of my male clients. Yes, they also struggle with issues like anxiety, depression, panic, and substance use, however, lack of intimacy is a major source of distress.
Some of them reference JP. More than one has asked me directly what I think of him and his philosophy. One showed his favorite videos and asked to talk about them. I have mixed feelings about JP. I've been aware of his stuff for about two years, and I've read other books/articles related to men and masculinity for many years. I'm not surprised to hear male clients struggle with intimacy, but I have been surprised at the consistency and intensity with which it shows up. And by intimacy I see everything from "I have difficulty making/maintaining friendships" to "I can't achieve/sustain an erection and therefore I'm not a man."
So, I think it's unwise to simply dismiss JP. It seems he's found an audience and has tapped into something many men (young men?) experience.
edited to ask: other folks doing clinical work, what's been your experience working with intimacy issues with male clients?