Why when given a cancer diagnosis do doctors automatically think that your willing to have treatment  

Is it an automatic thing,  is it something everyone with a cancer diagnosis does? 

Is there anyone who's had a diagnosis that's thought no , no thank you treatment isn't for me ?

I was diagnosed July 2021 with stage 3 breast cancer,  they removed the tumour and lymph nodes,  I refused chemo and radiotherapy and refused the hormone blockers that were offered .

A year later and I've been diagnosed with stage 4 breast cancer thats spread to my lungs,  my own fault yeah I know.

I tried the hormone blocker as that's all that was offered to me at this time , I couldn't get on with them which is one reason why I didn't take them last year , I KNOW my body and my body reacts to most medicines but I thought I'd try .

At this stage the oncologist is giving me a few months break from treatment seeing as the mets are only small then he's going to look into what other medication I can take whilst at the same time realising there probably isn't much I can take due to how my body works with medicines. 

But here the but , we all know stage 4 is it there is no coming back from it, we all know the final outcome so do I want to be ill from being on medication for whatever time I have left or do I want to be able to function as normal?

I already know that answer,  I want to function like a normal human , I'm well aware I'm being selfish and I don't really care , this is my life not anyone else's .

So my question is am I the only one who thinks like this, surely not?