Someone is bound to say this so I might as well volunteer first.
“Design is not just what it looks like and feels like. Design is how it works.”
I completely empathise with your pain, having witnessed a company ignore users and design what they feel like designing, what they want to show as sellable, and was a sexy set of pictures to entice the CEO. More than once.
You started with an excellent premise, reiterating that form follows function, as any good product designer understands, but then digressed to meaningless platitudes like “design connects us all”. Sticking to your original point though, I’d want to press that visual design and branding hold a key place at all stages of product or service development, evolving and iterating alongside the functional design so that all users can be both satisfied as well as delighted. You’re right to point out that craiglist isn’t pretty, but it is clear and it is fast, which fits the user’s need for desirability. Often we assume anything beautiful is inherently better; but sometimes ugly works just fine thank you very much.
“I really wish Craigslist was more attractive, with creative use of whitespace and subtler typographic choices”, said no-one. ever.