This is not comparing being gay to a physical deformity- this is an analogy. Think about it. In the commercial it's about a person who is afraid of letting their true self show because of fear of rejection. The big hand displays how it sets them apart from others, a trait which the character at first hates because he doesn't want to be treated differently. But when he meets this man, whom he loves, he realizes he can't worry about being different anymore if he wants to stay with this guy, and that if he wants to live a happy life he needs to accept himself, and his sexuality, aka his "big hand."
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