The important thing to understand is that betting odds are not a prediction of an outcome.
They are a simply a balancing act that aims to ensure the bookmaker will make a profit - no matter what the outcome is.
It can be implied that the betting odds reflect the crowd-wisdom, of what people think the probability of the event is - but in no way is the system designed to be a predictor.
When a bookies takes bets, it is trying to ensure that no matter what happens - they will never pay out more to either side, than they have taken in total. They do this by constantly balancing the odds they are offering, to entice people to put money on the unbalanced side. Given enough bettors, this works well.
long example incoming
As an example, say we're betting on an unbiased flip of a coin. We know the probability is 0.5 for each side, guaranteed.
The bookie in this case, for simplicity, is going to take no margin - that is, they are for some reason, an unrealistic charity case who simply wants to avoid losing money - in real life, the odds will not add up to 1.0 at any point and that part is the margin the bookie will take profit from.
So for the starting odds, the bookie will set the bet at what they expect people to go for, in this case they expect everybody to split their bet evenly. So we get the odds:
People come along, and they start betting. You'd expect it to spread evenly (like the bookie did - hence the initial odds), especially since you actually know the exact probability of winning in this case.
However, a TV psychic recently explained the importance of "always betting on heads" to the masses - as such, the bets that come in are actually:
$100 heads (@1:1)
$10 tails (@1:1)
So now, despite us knowing the true probability is 0.5 tails, 0.5 heads, we've now got the following liabilities.
If heads, we lose $90 ($10 kept from tails bettors - $100 paid to heads bettors).
If tails, we win $90 ($100 kept from heads bettors - $10 paid to tails bettors).
Clearly, we want to balance this, so that no matter what happens, we do not lose money.
Let's say we go back in time, as we're seeing the first few bets come in (we'll ignore these, in real life we would still pay out at that rate) - we want to start balancing the odds. As we're seeing 10x more bets on heads than on tails, we might for example adjust our odds to be:
1:10 heads (bet $10 to win $1)
10:1 tails (win $10 for every $1 bet)
Even though we know they actually have the same probability of being true
As such, when we get the same bets in:
$100 heads (@1:10)
$10 tails (@10:1)
So now our liabilities are:
If heads, we get $0, ($10 kept from tails losers - $10 lost to heads winners ($1 paid out for each $10 bet))
If tails, we get $0, ($100 kept from heads losers - $100 lost to tails winners ($10 paid out for each $1 bet))
So now we have balanced our liabilities, no matter what happens - we're guaranteed not to win or lose money. How does a bookie then actually make a profit? They add a margin on each bet, so rather than 10:1 vs 1:10, you'll see something like 11:1 vs 1:9. But the key thing is the same: the odds are set against the spread of bets, not against the actual outcome of the event - even if there is a correlation between those two things.
And hopefully clearly from this, just because the bookie here was giving 10:1 on heads - does not affect the fact that the unbiased coin flip, still has a real probability of 50% heads, 50% tails.
The only information it gives, is that for some reason - the bettors put more money behind heads than they did tails. (and there is no indication if that was a single super-rich bettor, or an even spread of small ones - you do not even get that information)
Of course, the reality of deciding how to adjust the odds isn't simple, and there's a lot that goes into it.