I think borrowing/lending and investing are two different aspects although very similar.
If you are lending some money to a friend or a person, you don't care what they do with it and what they bet on, as long as they have a way to pay it back.
When you are investing in a player you are accepting that the person might fail and trusting his abilities to win. In that case, if he loses then you have to just accept it and move on.
I've never funded a player but I have tailed sports bets from experienced guys and gave them a tip when it hit.
That is why if we want to finance someone or borrow money from someone, we have to know whether he is able to pay his debt to us or whether he will not want to return the money at all. Moreover, this is a friend who we probably hang out with a lot so some of us might feel bad if we don't lend him money. But if it is going to be used for gambling, we have to really think about it before we lend him money because in gambling, a person will not always be able to win and that means he has the possibility of not being able to pay his debts.
Likewise, with investing, because every investment will definitely have risks, we also have to think about these risks. If we can accept whatever will happen, we can lend him money, but when we cannot accept the fact that he may not return the money, we don't need to lend him and can give the excuse that we need the money to meet our daily needs.