Nonprofits try really, really hard to make money well beyond their near-term expenses. Wikimedia Foundation is (in)famous for this.
First, they want a rainy-day fund to cover fixed expenses when income fluctuates. Second, and more importantly, they might want to create a massive endowment that provides them with stable income so that they're not beholden (or accountable) to donors or their usual business partners.
The only difference, at the end of the day, is whether they ever want to IPO.
The other reason a non-profit tries to more than cover its expenses is to accomplish its mission.
The point of non-profits is that their goal is to accomplish something other than profiting. Sometimes the goal can cost a lot of money to accomplish, often much more than just the cost of paying its employees.
For example a non-profit that raises money for cancer research might have very low costs and raise tons of money without raising eyebrows. Because they put the majority toward their goal, and everybody understands the goal, and "profit" is not that goal.
They're actually a great example, they have a defined amount of financial runway they maintain, and they don't exceed it. You might notice they don't leave the fundraising banners up all year.
Web hosting ain't free, especially at their scales.