That's the definition of FUD.

Nobody is replacing the standard syntax-based completion with LLMs. Using LLMs is a new approach to providing code completions that span longer than the next identifier. If you don't find some completion features useful - that's ok, nobody judges you, you are free to disable them.

Does it make sense to turn off code completion by default for everybody because of these few users?

The default settings are what's useful for most people using the IDE, and most people find LLM-powered completion helpful at least to some extent. It's similar to complaining that standard code completion is enabled by default. Yes, maybe there are a few people that prefer to memorize their code.

The only LLM feature that you'll encounter if you open the editor and start writing code is completion powered by local and remote LLMs. If you don't need it, it's just a couple of setting in completion settings.

If you're using a commercial license, nothing changed for you here. With non-commercial license you're not paying anything, and you are still free to opt-out of the data collection.

What exactly is your experience with "AI enshittification" of CLion, or do you just believe all the FUD Sos is spreading?