i think that in many situations if someone close to you does those things and still doesn't lose weight they might be lying to you about what they are actually doing. There was this guy i knew Andy that was riding his bike HARD all the time, and claimed to be eating right but he was always at the bar drinking beer... not too difficult to understand what the real problem is there.
While I will admit there could be some isolated issues such as hormonal imbalances and certain diseases of the organs that could be the issue, for the most part this fat acceptance is dangerous because being obese is dangerous.
I'm not saying that anyone who is fat should be looked down upon or bullied... absolutely not. But to suggest that "it isn't your fault!" for 95% of overweight adults, is just a flat - out lie.