The complaint here isn't that there is a contract; it's that the user is deceived by dark patterns into thinking they've entered a plan with no contract.

By contrast, going to tmobile.de or blau.de, even without speaking German it's extremely clear that prices are based on 24-month contracts. Never is the monthly price mentioned without a clear label below it indicating 24 month terms. Blau even takes it a step further and places the text twice in the box, once in the UI and another time directly below the price.

True but this would indeed be considered very unusual and surprising for software if it wasn't indicated explicitly.

I just checked and while they do only indicate "X €/month" on the product page, as soon as you enter the checkout process it says "yearly subscription, monthly payment - Y €/month" with the additional options "yearly subscription, advance payment - X €/year" and "monthly subscription - Z €/month". I'm not sure how they're getting away with the misleading prices on the product pages tho (usually there's at least an asterisk indicating this comes with additional conditions and obligations).

That's what I was thinking. If you want to get out of a contract early, you'll usually lose some money. That's true for rent, public transit passes, and many other types of subscription.

If there are no consequences for bailing out of a contract, it makes them rather pointless.

But then there's always some kind of a cool down period, i.e. a time during which one can cancel a subscription without penalties.

At least this is how I expect things to work here, in the UK.

There's a 14 day cancellation period after you sign certain contracts, but I don't know the details.

Beyond that, a contract is a contract.