This is easy to explain. For one thing, these “wipes” are a new thing. Most of us who prefer official servers rely on the assumption that Funcom won’t wipe official servers. That assumption has held for years now, for the vast majority of official servers.
Second, there are no server wipes on official servers. There’s downsizing, which isn’t the same, even though some players will be affected in almost the same way they would be with a server wipe. There are also the new rules, but those don’t end up in a whole server being wiped, only the builds that are against these rules.
For starters, just finding that private server can be a needle-in-a-haystack scenario, except you’re not guaranteed that the haystack even has a needle.
Before even considering whether I gel with the the community and administration, I need to find a server that satisfies the following conditions:
- It’s a game mode I like.
- I prefer PVE-C, but will settle for PVE if I have to.
- The ping is decent.
- The settings are close to vanilla.
- I’m not into 5x harvest multipliers or 10x XP multipliers. I’ve even seen one server where sprint cost multiplier was set to 0, so you could sprint endlessly.
- The mod list is short enough and doesn’t include stuff I hate.
- I respect the effort and the skill of the people behind the Age of Calamitous, but if I wanted to play a generic Tolkien-derivative MMORPG, I would have picked something other than Conan Exiles.
- No requirement to hang out in Discord voice chat. (Yes, there are servers that require it.)
- No onerous rules.
- Some servers have rules limit the building sizes way too much for my taste.
- Others have a whole process that requires you to come up with a backstory for your character and get it vetted. I respect hard-core RPers, but I’d rather go play a TTRPG if I wanted that.
Even if I find a server like that, I still have the following risks to worry about and problems to deal with:
- Is the admin good?
- Admin abuse is something to worry about, but it’s not the only thing that can go wrong. Being a good admin takes a lot of work.
- How long will the server last?
- Every time there’s a major update, I won’t be able to play for at least a day, often several days, because of the mods.
- Speaking of which, what happens if the community wants to add another mod?
- Every new mod is another thing that can break during a major update.
- It’s also another thing you could get used to, a thing you might not have again if you ever have to move to another server.
- What if it’s a mod I hate?
On officials, I don’t have to worry about any of that, except the admins, but even that is a different concern than the one I have on privates. True, I need to worry about whether I understood the rules correctly and whether a malicious report will happen to be seen by an overworked (or negligent) admin, but there are some mitigating factors there:
- Getting wiped by a Funcom admin due to malicious reporting is not substantially different from getting harassed and griefed by some troll clan before Funcom started moderating officials. Both scenarios end up in having to move to a different server and starting from scratch there.
- Speaking of which, moving to a different server is not hard on officials. You don’t have to get used to a different mod list or the subtle (or not-so-subtle) effects of different settings.
So yeah, I prefer official servers. In fact, in all my experimentation with more than 10 private servers, I’ve only found two that I liked, but not enough to stay there forever:
- @Ramtex’s Lawless Sands was an excellent place. Sadly, my ping on it was insanely high, so I had to move on.
- @Larathiel used to run excellent PVE servers. He was a great admin and the community was awesome. I eventually decided to go back to officials because I missed PVE-C and because I didn’t like waiting for the mods to get unborked on every update. Neither of these reasons is @Larathiel’s fault.
Sorry for the long-winded post. I hope at least a portion of this wall of text is helpful to someone 
EDIT: Added some past tense and sadness.