As the title says, Reddit replied to my GDPR request to delete all my data saying I had to do it first, which I suspect is in violation of GDPR law.
Reddit’s argument is that to comply with GDPR, they just need to dossociate your account from your posts, so the latter cannot be traced back to you. However, the argument could be made that the posts themselves are enough data to be linked to you.
Is there any type of response that could be framed in legal terms to make reddit really remove all the content from my account?
I think it’s untested whether this is legal or not; it’s in a legal grey zone. Try to find an online script to help you delete all your posts. Alternatively turn the question to your national agency which handles GDPR compliance.