I work in data compliance, and this form is actually pretty incredible, IMHO.

This is NOT their opt out form, which is located here (a tab over): https://gmcontactpreferences.com/email-preferences.jsp

This is them performing a deep scouring across all of their marketing databases for your information. Junk mail, phone, etc. (Letting you include multiple phone numbers is a nice touch). This is actually a pretty big deal since these systems probably don't even talk to each other.

You even have the option to "retrieve" the data on your email address.

Never in a million years would our org let us put this much effort into this without the threat of lawsuits.