This is why we have a hardcore "no sympathy" rule here.  They're not wrong, but that genetic component only changes your BMR by 5% or so, at most.    But the butter golems see anything about genetics and immediately use it as an excuse to be 400 pounds.    A smart,  rational person looks at a 5% variance and says "I'd better be careful not to overestimate my calorie usage then in case I'm an outlier".  A ham uses it as an excuse to give up.  Because if they were rational, they wouldn't be fat in the first place.