I think there are plenty of groups to join (via meetup) for both sexes if you are in a big enough city, but you can't force lonely people to go out and socialise. They have to want it for themselves.

Wanting it is only half. I feel as if I fit into a category of those who deeply wish they could socialise more, but feel strong discomfort in that initial approach.

For nowI live in London, which is the essence of a place in the world where everything is there for everyone. The old quote by Samuel Johnson about those who are tired of London are tired of life, still holds its meaning in so far as those who are not yet tired of London have the wealth and the social skills to most benefit from it. However outside of the City in the outer boroughs, the loss of club house facilities, music halls, and general public good will in interacting with each other has slipped so far into obscurity that so much of the culture of the place has been lost as the general population become shut-ins, myself included.

I have had a look at sites like meetup, and when I feel particularly rigorous will look around elsewhere on the web for local newsletters or even specific sub-reddits, but with the layout of meetup in particular, a lot of these services can be unintuitive and off-putting to those who just wish to sample everything and try to get used to new company. Signing up for everything and entering into correspondence with all manner of strangers, often quite abrasive as Londoners go, is off-putting. Reddit is the safe place to voice concerns seemingly to nobody in particular, but there are so many ways which can lead up to making somebody feel uncomfortable and wanting to bail. Also I have found directly that a lot of clubs actively scorn the interest of single men. Everything from film clubs to ramblers associations all favour the attention from either the elderly, or failing that couples and single women. Contrary to the opportunities on offer, for a man the expectation is to just shut off all emotion and not get hurt from being turned down from places. Never mind the fact that constantly making some men feel unwelcome but allowing the priviledged ones to carry on as usual is just preventing all but a few from forming that level of acceptance within themselves for when they grow older. Or even that the only reason the men are really there is because they want to feel involved with something and not stir trouble. There are notable exceptions where the demographics construct a more inclusive environment for men, but then the problem is that it can tip rapidly in the other direction and everybody are just grumbling men who grow cold towards new blood because it meddles with their small close knit community.

Perhaps I'm just a rare case and I'm warping things all out of proportion through my own experiences of how I've been treated before, yet the number of others who complain online prove that if nothing else, there are more who need a little aid every now and then, and everybody is always ignorant to the fact that almost as if by sub-conscious routine, their only reply to those who ask for that help is to shoot them down and tell them to deal with it by themselves. The cycle isn't broken.