It's exactly the same thing as when one of my neighbors has a TV they want to sell for $10, and I buy it and sell it to a friend across the river for $11. Without my knowledge the neighbor might not have sold it at all.
No, it's not the same, because with HFT the buyer is not across the river, he's in the very same stock exchange. He will see the TV set for sale, whether you meddle in the affair or not. Thus all you've done is made your "friend" pay a dollar more than he otherwise would have to, pocketing said dollar yourself.
There are ways within this system to cheat, but arbitrage per se is not cheating, it's implementing the system of equilibrating the markets.
But we aren't talking about arbitraging between markets. We're talking about a single market, a single stock exchange. And while there's value in arbitraging between points of time - essentially storing resources when they're plentiful and releasing them when they're scarce - we're talking about microseconds here.
As for von Rothschild, you do realize that that was basically insider trading? As is HFT. They're both based on some market participants having information that has not yet have had a chance to become public knowledge. That is the problem with HFT: someone is using their special position in the market to do trades Joe Average possibly couldn't. That's cheating, so why shouldn't Joe use his special position of sheer numbers to have his representatives shut it off?