Almost universally, if you are in a Beginner Freshwater forum, you can very safely assume that if someone mentions a betta, they have a common Vieltail, or maybe a Crowntail, Betta Splendens that they bought in a little cup from a big box store, and was bred by one of the mass breeders.
Experiences with completely different species hardly apply, and I stand by my comments. But if you insist, BETTA SPLENDENS do like to flair, but rarely do any damage. They are far more frequently picked on that the reverse. There may be cases of individuals with a mean streak, but these are the exception, and not the norm.
But seriously, now, what beginner has access to wild or specialist species of Betta and treis to keep them in a community tank? Could it possibly come up enough times in the lifetime of our sun as to need this disclaimer?