> Healthy markets are markets where everyone has access to the same information.

I don't want to sound condescending, but did you read the article? One of the points is that this is exactly what HFT accomplishes:

Bob wants to buy a lot of Apple shares. At this point he has more information than all other market participants. He knows that in a few moments, the price of Apple shares will rise. Is the market for Apple shares -- at this point -- an unhealthy market, because Bob has access to more information about it?

If Bob's large order is larger than the current number of open orders, then an HFT algorithm might see Bob's trade -- where he buys some of the stock he wants to buy -- and assume he wants to buy more, so it adjusts its orders accordingly. This very act disseminates information into the market about Bob's large order (if the HFT algo is right, if it isn't it loses money). Information about Bob's future order is now more evenly spread between market participants, though a higher ask price, reflecting Bob's large future order. The information that each participant has is now more equal than it was if no orders were adjusted, because the buying price has risen as a result.