Focus on organizing and socialism and let any friendships be natural. It's not practical to completely separate one's social life and political life.
Friendship doesn't always stay that, though. Be careful and modest and never let it become a dating scene. Lefties will date but there is a huge difference between those who happen to date vs. an organization that allows or even promotes harassment, which is unfortunately very common. Similarly, nobody should be put in situations in a lefty organization where they are being sexualized or where there can be any perception of favoritism or discrimination. These should be places where one's political contributions are what are valued.
If these things aren't taken seriously then the org will eventually implode from not handling abusive situations appropriately and instead relying on however the current leadership team (usually defensively) responds to complaints. This is one of the worst and unfortunately common scenarios in political organizations and is a much greater threat to your organization (and people that want to work within it) than any feds or cops. The Best rule of thumb is to be humble and empathetic and plan for how you are going to handle situations with social fallout.
As a different example, you may also have people in your organization that do not get along and begin fighting. Sometimes it's even pretty clear when one person is in the wrong and the other is not. But even then, the person that is in the wrong may weaponize anything they perceive to have caché in your organization. For example, race or gender or sexual orientation, etc. I've seen it happen many times. A harasser wraps themselves in an identity to deflect from their own behavior. So as an organization, you want to prepare for these scenarios because it is part of promoting comradely behavior and being a space where people actually want to be and work. And you need to develop strategies by which you will discriminate between true and false claims and reach reasonable conclusions to protect the members of your organization. Don't worry about the image of the organization itself because if you act correctly in individual cases to protect the members of the org you can always explain what happened and why. In contrast, many lefties make the mistake of trying to protect the org over its members and this nearly always backfires.
Anyways this is how I recommend approaching the building of a space where commies can be friends. Keep the focus on organizing, education, and being a place where people can safely be. Plan for the worst so you can head it off before things get too far and so that you have tools to handle negative situations correctly.
I don't make friends with people whose views contradict mine. That being said, I basically have two friends, one of them doesn't care about politics (she's young and lost) but we do agree on important topics while the other is a leftist but does not care much about politics either. The only person I can fully discuss politics with us my boyfriend, which I'm very grateful for.
As for making friends, I would probably make friends outside communist circles in the future. Having come to the same conclusion is not necessary for a friendship to work, but not agreeing on major issues is. The communist scene in my country is mostly old people who don't represent ML values, just a force of habit. The anti communist propaganda is really strong so while many young people agree with what we are saying, they are afraid to associate with the commies or have no/false information about the movement.
I have been active for a few years within our party now and I can't say I have made friends. Sure, I like working with them and we have hang out occasionally but that's about it. We get along fine and we can do the work that's required from us.
My actual friend group is diverse. Over here in Belgium it is pretty left leaning but not always communist. They're just people who I met throughout the years with whom I share interests. They do help me out with party stuff and they are sympathetic towards my efforts, so that's good I think.
Back in The Netherlands I have my childhood friends group and they are probably even further removed from me politically speaking. One of my friends even is a politician for VVD, the right wing neolib party. But they are still my friends with whom I have experienced so much. Whenever we get together we have a lot of fun despite political differences. I try to keep looking at the person behind the politics. It's what we do with our party whenever someone says they for far right for example. You can either alienate them or try to talk to them to see where there is common ground and to see if you can get them on your side.
Things are almost never that black and white. I get along fine with most people and my world would remain very small if I instantly shut down connections with people that have different views. That being said, if one of my friends was an outright neonazi I'd cut ties. I do have my limits.
