He/she just means that if a bet is genuinely underpriced, the expected value of taking it will be positive. (So if you can reliably find these bets, you'll profit in the long run.)
The odds reflect the horse's supposed chance of winning or placing (or whatever else it takes to get a payout), not its expected position -- so this isn't a case where you can be aware that the horse is underrated, but have no way to make a +EV bet on that knowledge.
Yeah over the long term, but I thought this was already implied. All I'm saying is that "beating" other bettors is not enough to ensure success because of the means by which payouts are made. I suspect you feel this is also implied though, so I think we're probably on the same page.
Exactly, for example yesterday I placed over 5000 bets, not all of them won but as far as my strategies were concerned they were value and should therefore be in profit over the long term.
The odds reflect the horse's supposed chance of winning or placing (or whatever else it takes to get a payout), not its expected position -- so this isn't a case where you can be aware that the horse is underrated, but have no way to make a +EV bet on that knowledge.