Having in mind that no game is a sure game makes gambling to be of the mind and not of public opinion, because regardless of the level of the support the public may have on a team, it can never aid them to win a game that their poorly played, so for a gambler what we have to know is that, there will be a time when we leave the public behind and focus more on our own inner believe and convictions.
Having the mindset of what gambling really is which is risk and luck, helps us alot as both spectators and gambler's, even player's also need such mindset to build inner confidence.
I agree with what you said, indeed there are many things that can be our own considerations when we are going to gamble, but sometimes we have to trust our own choices and instincts because believing in what is out there does not make it easy for us to win at gambling. Moreover, in my opinion, focusing on one's own beliefs is not much different from believing in the many news outside, but for people who are looking for profit in gambling, they are more likely to believe in things that are out there.
With that mindset, each individual, in my opinion, can determine them in the future, now if they believe in things that are more public, it can allow them to be more aggressive in gambling, with the reality that the possibility of disappointing results can make them look for new ways or strategies that they believe can make them win for sure.