To date, on the rare occasion that requests have been made to remove posts containing personal info we do indeed remove them, so as far as GDPR is coming into play that is something we have always done anyway. In terms of completely removing all posts, GDPR requires that users have a way to delete their personal data. It (the EU) specifically defines 'personal data' in the GDPR regulation Article 4 as:
‘personal data’ means any information relating to an identified or identifiable natural person (‘data subject’); an identifiable natural person is one who can be identified, directly or indirectly, in particular by reference to an identifier such as a name, an identification number, location data, an online identifier or to one or more factors specific to the physical, physiological, genetic, mental, economic, cultural or social identity of that natural person;
So in those terms information on your profile (name etc) could be considered to fall under those guidelines. You can edit those details or they'll be removed if you cancel your account. However posts within the forums do not generally qualify as personal data. If a post or posts contain personal data then we can work with you to remove that personal info or post(s)/content, but as I said earlier that is something that we have always done anyway on the rare occasion someone has asked.
Hope that brings some clarity.