Exactly. I respect their decision to go closed source if that's what they need to do to make it a viable business, but just be honest about it. Don't make up some excuse around security and open source.
it's not necessarily about people self hosting it, it's about people preferring to pay for hosted stuff that is open source (e.g. I pay for Plausible).
Now it's a lot easier to rewrite open source stuff to get around licensing requirements and have an LLM watch the repo and copy all improvements and fixes, so the bar for a competitor to come along and get 10 years of work for free it a lot lower.