Pretty much every adult fat person has attempted diet and exercise to resolve their weight issue.
Saying they should try this first at this point in the game is like having your support case escalated 5 times already and them saying "have you tried turning it off and on again"
As best as I can tell, people are very attached to having achieved their body weight through whatever means they have determined are valid and derive self value from it, and believe that GLP-1s are cheating to achieve a result they worked harder for.
What you need to understand is there are a lot of people where all they have is being skinny and appearing to be healthy. Without that, there's nothing left for them.
For a long time, there has been a moat that they can use as a justification for why they're better. They can say "well I work hard, I eat right, I put in effort!" The idea that others can achieve that without any of that means... well, they did it all for nothing. In their heads.
The dirty little secret? Many of them don't do any of that, it's just a delusion. Always has been. I'm skinny, you think I go to the gym? Fuck no! I should, but I don't. And I eat whatever I want.
But if a lot of people have to face the reality that their most redeeming quality is nothing of their doing, that would ruin them. Ruin them. They could just, like, get achievements or something but that's hard. Continuing the delusion is easy.
There's not a single qualified doctor out there that would promote drugs before preventative measures.