The reason many private servers have disabled Living Settlements is due to several serious bugs not limited to: dying worker/crafter thralls, thralls opening doors for enemies, bunching up at one station such as the thrall pot, getting stuck inside building pieces and interfering with some mods.
You have options luckily
In singleplayer, co-op or your own private server you may enable Living Settlements in the options.
Find a private server that has it enabled.
Or visit an Official server, since those all have Living Settlements enabled.