I’m a pretty strong believer in the right to be forgotten online from a privacy and safety pov. 

The only argument I’ve heard to counter is that a delete function could put someone’s freedom of speech at risk, negating the point of nostr. I don’t really see how that’s possible though because the danger would mostly (in this case) come from relays censoring, not the individual, which is possible in the current state of things (I think).

If relays stop hosting your content to save money in the long term, won’t you be deleted eventually, as well? 

Having a “request to delete” button is fine in most cases, even if people understand some relays may not comply. You are still lowering your digital footprint if a stalker gets out of control etc.