I know it was deliberate, and deliberately hiding the story.
Certainly several locals will prefer the name they grew up with. Some find it rolls off the tongue better when speaking English, or just because they used Bangalore for many years already. No such change will ever have 100% coverage in such a short time, yet I think it's worth consciously respecting. Locals will use both interchangeably because it's often used informally, but I think for anything official, it's important to use the correct and official name, which is Bengaluru. Such as here, this is not an informal post by YC but an official announcement.