There's a very real possibility that FiftyThree is going to get impacted in all kinds of searches because of this. I don't begrudge them for taking advantage of a marketing opportunity that will get written about in the media that they'd be fools to not take advantage of. Their business could conceivably be on the line.
You're certainly free to disagree or feel all the sympathy you want to for Facebook here, but I don't think most people would see it the same way.
These are the risks of choosing a product name that is one of the most common items in the world. The benefits are familiarity and comfort; the risk is that anyone can start using it.
>If they make enough stink they can maintain their brand.
This is it exactly. Copyright and trademark are not the same thing, but many people confuse them. You have it right: With trademark the burden is on FiftyThree to defend it. The fact that they are doing that so politely makes me like them more.
You're certainly free to disagree or feel all the sympathy you want to for Facebook here, but I don't think most people would see it the same way.