The GDPR and CCPA give you the "Right to be Forgotten." You can email Reddit's legal department specifically asking for data deletion, but they often ignore individual requests unless you are in the EU.
If you are accessing Reddit without a VPN or proxy, the site is likely logging your precise location and device fingerprint, tying it directly to your posting history. reddit privacy megathread
The passion behind the "Reddit privacy megathread" is fueled by a series of major events that have eroded trust in the platform. The GDPR and CCPA give you the "Right to be Forgotten