Seeing as how nearly all multiplayer games these days are essentially closed servers with match making (dedicated server software is not made available for setting up private servers, and the server uses algorithms to team you up with/against random players) — essentially the server equivalent of DRM — are there any games with at least PARTIAL player freedom? A game where you could at least decide whom to play with and set up private matches? Finding some people to get to know and play with/against? Clans? Groups? Clan tournaments? Forums?

You know, the golden days of Q2, AQ2, UT99, HL, CS, W:ET, and so on.

Or has multiplayer been so gutted and utterly destroyed? You might as well be playing against bots...

I've nigh on given up on playing anything modern :/ The good old hardcore games are still fun, and there are plenty of servers still being run, but sometimes I'd still want to try something newer as well.

Is there anything at all?

Now and then I end up asking the same question again and again in various places, always hoping to find something. Sadly, it seems multiplayer is dead, or at least proper multiplayer.

I haven't touched multiplayer in a decade or more - at least not to any great extent - so has the private server really become that scarce? That would be a shame. Once you find a good one that has rules fitting your play style - or running the mods / conversions you like it's like multiplayer heaven. And you tend to see the same mix of people on those servers (not always 'clan' affiliated), so there's some informal continuity to be had.

Stay away from AAA developed games. BF1/SWBF/CODs.. these aren't the games you are looking for.
DO NOT stay away from indie games like insurgency, Squad or Day of infamy. These are the games that give you GOOD FPS action. But it's NOT your usual runandgun style.
They are out there, just not as popular with the big corporations, for obvious reasons (WE WANT YOU TO BE A SLAVE FOR US. SO WE WANT YOU TO ROBOT LIKE US).

you could try the battlegrounds in tera online - there's little rules to learn and the action is exciting. once you reach level 30 you can do iron battleground with tanks and kuma royale where you get transformed in some cute bear and fight with 7 skills. or you can become the kuma boss if you think you're good. and once you get to max level, 65, you have access to all battlegrounds like gridiron, corsair stronghold, etc. in most battlegrounds you get exactly the same equipment as everyone else so there's no reason to complain that the opponent is higher level or better geared. problem is that you only do battlegrounds to get better equipment or money. but even if you get best equipment for PvP, named Conflate, you got nothing to do with it because the high level maps are all safe zones - you can't kill people there. that sucks for me so i quit tera but i admit, it was kind of fun

Verdun is pretty awesome.
Check out Day of Infamy. It's a remake of DoD made in Unreal 4. It's in beta right now but it feels just as polished as Verdun and it's only getting better with age.

Perhaps I could mention that online multiplayer games on Nintendo consoles typically use friend codes for multiplayer. In other words, you enter a friend's code in your game, and then your friend enters your code in her game, and then you can play together. In fact, I think some Nintendo games might only offer multiplayer with friend codes and not randoms.

On the other hand, I still refuse to get modern Nintendo products because of region locking and DRM on digital downloads. (Then again, I could point out that I avoid multiplayer.)

Yeah, they aren't exactly covert about it either! I'll have a look, just because it isn't nonstop hold-down-the-fire-button doesn't mean it's not good.

People do join, just keep in mind that you have to get into an empty server to bring more people. I've joined one empty server at Xonotic, despite most of em being empty and people kept joining in.

Xonotic and OpenArena are alive. From non-3d, Project Zomboid has platform-unlocked multiplayer.

Terraria.

Insurgency, Day Of Defeat, Day Of Infamy, very good games! Thanks!

Glad I could help. They are pretty amazing games huh.

I am NOT sure what kind of game are we talking about.