You explained it well with arguments but people still can't understand. They follow very primitive logic that more is better, they can't understand that the whole Thesaurus and a tiny BIP wordlist, both of them are equally safe for generating 12 or 24 words seed phrase. To be frank, no one ever had a problem with it, no one's wallet has ever been hacked by bruteforcing seed phrases and I don't really understand why are people looking for solutions for a problem that doesn't exist.
Maybe people don't understand, maybe people are lazy to dig into the documentation of how BIP39 actually works. I don't know what exactly the problem is. You can read and try to understand BIP39 at various places where it's explained. For me a nice spot is here:
https://learnmeabitcoin.com/technical/mnemonic, it's visual, some explanatory code for code nerds and lots of details and links.
Who doesn't understand that?
It's certainly laziness, I can tell you from personal examples that people don't want to bother learning new stuff.
learnmebitcoin.com is indeed a great website. Personally I love reading "Mastering Bitcoin" by A. Antonopoulos which is one of the best books I have ever read, but it is a bit more difficult.
Then again, anyone can read both, but the question is, are they willing to do so?
Most people think what Synchronice says, that the more words, the more secure the phrase is. I would give a point though to those that don't know what a
bit is in computer science. Unfortunately (and fortunately too) Bitcoin requires basic computer knowledge. But I find this as a strong positive of Bitcoin's.
Bitcoin is an incredible amalgam of Cryptography, Math and Computer Science. But luckily we are here to help and be helped.