>Why does it need to be an all or nothing proposition?

This can depend on personality, circumstances, etc. IMO if someone is stuck in a rut and decides the only way out is a complete polar switch, good for them. At least they are making a change for what they feel is the better. They might already know that they don't do well with half-switches and tend to fall back into the same orbit. Or they might just be really overwhelmed in general and find the feel of small yet firm changes appealing.

It can be annoying to have to put up with others' all-or-nothing viewpoints, but it can still be useful to appreciate that their perspective might be informed by experiences that differ from our own.