Q: Is this legal on Apple's part?

Debit cards are no longer accepted in many areas. Either update your information

or contact iTunes support for assistance.

https://www.apple.com/support/itunes/

Payment methods you can use in the iTunes Store, Mac App Store, App Store, and iBooks Store - Apple Support

AppleID without a credit card:  http://support.apple.com/en-us/HT204034

Hello, I am more than happy to help!

I have experienced this problem before. The reason it will not let you do this is because that Apple does a check to see if £1.29 is on the card, this is to make sure that the card is valid (No money is withdrawn). You must go into iTunes Store > Apple iD (at the bottom of the page) > View Apple iD > Payment Information, then it should have a tick next to your card company (e.g. Visa, MasterCard etc.). You should then click none. Now you should be able to download free apps and updates.

Yours Faithfully,

Pro Mac

Hi Pro Mac i have the same problem...but is not exist the button none...:(

pretty sure the purchase contract does not promise any updates ever the developer can update or not

so that part is not a valid complaint for you that apple does not let you update as you are not entitled to any updates after you purchase an app

the redownload would depend on what their rules says with such a big company and so few reading the license agreement then likely they got most stuff covered there

http://www.apple.com/legal/internet-services/itunes/appstore/dev/stdeula/

To answer your original question, yes, it's legal.

Check this article:

Why can’t I select None when I edit my Apple ID payment information? - Apple Support

hi,i try all is not work;(