How does as man admitting that he's lonely help?
As a concrete (and tiny) example: we enforce loneliness at the physical and policy levels by subsiding the construction of car-dependent suburbs: human socialization becomes defined by points of interaction (driving to the bowling alley, except you have no friends to bowl with), rather than transitory areas of interaction.
I didn't say that they were the same: I said that expressions of loneliness are stigmatized in men, and that we've developed social structures that create and enforce loneliness. They're separate points.
The stigma around loneliness doesn't as much cause loneliness as it ensures that the causes of loneliness can't be meaningfully ameliorated. To use a popular phrase: "the first step to recovery is admitting you have a problem."