10002 events are events containing a list of your Inbox/Outbox relays—see: https://nostr-nips.com/nip-65

I’m deleting them because some relays are retaining outdated events and lists. When Amethyst downloads an outdated list from a relay, it sends a new 10002 event with the latest list. Since relays aren’t deleting old events and Amethyst isn’t filtering to show only the most recent event, users who switch relays frequently (like me) end up receiving a ton of redundant 10002 events, often triggering rate limits, etc.

Not sure if I’m explaining this clearly, but I hope it makes sense.