Why are people so defensive when others share how they want to lose weight?

I might happen to be in the minority, but as a slightly overweight person, I know the repercussions of holding this extra baggage. I have bounced around from pre-hypertension to hypertension back down to pre-hypertension and weight issues are nothing to take lightly in my opinion. So why do people defend the overweight? Factually it’s potentially more detrimental that someone who is average weight.

What point am I missing here? I’m trying to keep an open mind about things? I truly don’t understand the message that is saying, “Sending a message that thin is good, is actually bad.”