I'll have to take you at your word as I don't have experience where you live. Here, friendly requests tend to be much less formal. As a further example, suppose my dog was in my back yard barking, and this annoys my neighbor. They approach me about it:
> "Hey, neighbor, your dog is bothering us. Could you take it inside?"
Typical response: "Oh, sorry! Sure. Come here, pooch!"
> "Hello neighbor. According to county code section 23, 'Nuisances', paragraph 3, 'Pets', your dog can't bark for more than one minute without violating the ordinance and being subject to a fine of not more than $85."
Typical response: "Get off my property, and if your kid ever throws a baseball at my house again, I'm going to launch it through your front window."
Normal-person requests are usually formulated like "hi, can you do this thing for me?" even if the person being asked is obligated to do it. Citing law is considered an aggressive escalation.
A communication between two entities who are not friends is not "friendly". This is clearly a formal request of a type that is even regulated by a law. You're almost certainly not asking your neighbor about something like this. You're almost certainly asking someone you've never met in your life. Not sure what about it needs to be "friendly" any more that asking a government bureau using some formalized process (like filling out a form) needs to be "friendly".
I've gotten requests from people asking me to delete their account, sent from the email address they used to register it, along the lines of:
"Hi, I've forgotten my password, but I don't really use my account anyway. Could you delete it for me?"
And of course I comply, because I want to be helpful. They asked nicely; I replied nicely. It's a pleasant and productive interaction from all involved. This is the social norm here.
But the example you outlined is not regulated by any law as a formal procedure. That's an ad-hoc request. Of course it could also be phrased as an GDPR erasure request, but I bet you'd definitely expect that to be more formal and more specific. After all, that would be a (formally) legal request, and not just something you may decide to do or not to do depending on how you slept last night.
> "Hey, neighbor, your dog is bothering us. Could you take it inside?"
Typical response: "Oh, sorry! Sure. Come here, pooch!"
> "Hello neighbor. According to county code section 23, 'Nuisances', paragraph 3, 'Pets', your dog can't bark for more than one minute without violating the ordinance and being subject to a fine of not more than $85."
Typical response: "Get off my property, and if your kid ever throws a baseball at my house again, I'm going to launch it through your front window."
Normal-person requests are usually formulated like "hi, can you do this thing for me?" even if the person being asked is obligated to do it. Citing law is considered an aggressive escalation.