What the other posts said and also we aren't born the same at all. We're individuals genetically and we're only similar to people that share a good portion of our dna like our close family.
Also like other people said, there's a problem with double standards, why shouldn't a skinny person be praised for working out? It's as hard for him as it is for a fat person,in fact sometimes is much harder simply because no one cares and no will praise that person.