Unless you run a non-profit, your company is also motivated by money and all your work and mission are only means to an end, which is to maximize the shareholders profit. That's why the company was founded, right?

Of course you have the right to deny a rise and let the employee go, maybe it really doesn't fit in your budget and/or you can hire someone else for less, but don't talk like the employee is wrong for searching a opportunity to grow.