Because it requires raising taxes and very few want that. Raise it on just the rich? Even the poor don't want that because they're just temporarily embarrassed millionaires.

Basically. It's a complicated economy issue. But lets say there's not just monetary debt, but also structural debt. Our infrastructure is old, a lot has to be repaired by making debts. But they refuse to, thing is, the bridges will collapse at some point, literally, if you don't build new ones. This will all come back to hunt our economy as no train will deliver, no truck will be able to use the highway as a lot of bridges are broken. Same with schools, you get less educated people, which then on average produce less wealth. In short term you save money, in the long term the world will move on without you. Every economist knows, a little debt is perfect as it works in sync with the capitalism we all live in. However the payment for the dept shouldn't outgrow the economy, that's the only rule. Making no new debts sounds good on paper, but no young person will say "thank you" when they grew up with bad education, a broken economy and an inhabitable planet. Now is the best time to make debts to fix big issues.

More like it doesn't want to get the money to maintain those infrastructure by going into further debt.

I'm not following German politics very closely but the article mentions that this restriction is in their constitution.

There was something in that genre in my province decades ago when a government dedicated itself to 'zero deficit' by cutting on infrastructure maintenance for many years. A bridge eventually fell. Classic story. It seems like a common thing.