It's not given freely unless consent is given, which in most cases it isn't.
As the operator of the website it becomes your duty to properly inform the user of what you are doing with their data and why.
If you send me an email, am I allowed to keep your email address in my mail logs, archives, and inbox? Hell yeah I am, you gave me implied consent to do that by sending me email.
Am I allowed to spam the email address you gave me? Of course not. But I can keep it.
Placing an automatic and extreme burden on the recipient of a communication like a website visit or email, which is exactly what the GPDR does, is just plain bananas.