Both sides have their points: some don’t believe, and others do. We just need to respect each other and never say it’s impossible to be profitable in gambling, because if you think that way, maybe gambling isn’t for you.
I have seen threads talk about having faith and belief when you bet, and now you talk about the right mindset, which makes sense, but it is not all it takes to win. When gambling, you are left in the dark because the possibilities of winning are indeterminate, optimistic expectations can keep you enrolling your funds even when losses continue. Be positive when you bet, as well reserve a portion of your feelings to incur losses and move ahead, it doesn't get rosy all the time in gambling.