As a gambler and a die-hard fan of a club that has been having a terrible season, would you bet against your club, knowing that their loss would be your financial gain? Or would you stay loyal and not bet against them?
As long as you are comfortable with what you are going to lose, it's ok to bet because you are a die-hard fan but it's better to cheer for them and not bet if you knew all along that your team has no chance of winning.
A die-hard fan will always hope for his team to win whatever the odds, but you can't be losing money when they are losing, your team will not give your money back if ever you lose.
I seldom against my favorite team it's like hoping that they lose and you do not represent yourself as a die-hard fan if you wish your favorite to lose.
There are other ways or chances to make money from sports betting but not at the expense of your favorite team.