What on Earth could you possibly mean by that? You'll magically make deep, abiding, social ties by riding a bicycle?

Well, it works for motorcycles. Sometimes I think I should get back into riding just for that reason.

Biking and walking to work are a couple of the loneliest activities I've tried.

I like to play "Will anyone smile and say, 'Hello!' back to me today?" whenever I'm out walking/cycling/running. The answer is more often than not, "Nope, no takers today."

I'm not against this idea, but an inattentive 23 year old driver who failed to yield killed a bicyclist crossing an interstate on ramp (in the crosswalk) down the street from my house last week, so there is risk involved.

Riding bicycles alone isn't going to help; its going to take decades of urban planning to fix the last 60 years of mistakes.

Just to give an alternate take on the comment from how others are replying:

Maybe look at it as joining a community, not specifically being about cycling. Being a cyclist gives you something in common with someone else that you can talk about it and, when doing it, it's rather visible. A running club, writing group, etc. can be similar.

Depends on what you mean by lonely, I think.

I'm a transportation cyclist, but I don't think being a cyclist has measurably increased the number of friends I have. It did give me something in common with quite a few of my friends, but I didn't meet any of them through cycling. For a while I tried joining a cycling club, but I found that I didn't have much in common with racing cyclists.

Being a cyclist did however does apparently increase the number of people who seem willing to harm me, unfortunately. That's not loneliness, but it's not good either.

Is this just dark humor or are cyclists just gregarious?

Not the OP, but I suspect that it's less about bikers and cyclists in particular and more a matter of coming into contact with other people who share an interest. Taking up golf or tennis would likely have the same effect.

this guy clearly lives in the city. Some people live in the suburbs where cars are needed to commute to work

Well, I live in the suburbs and ride my bike to and from work. Though my work is just 2 miles from my house. However, the vast majority of time I see nobody (other than people in cars) while riding my bike, so I'm not exactly sure what OP means by bike riding being a way to not be lonely.

For a given definition of 'suburb'. My commute is 10 miles each way, not a problem.