The answer is easy. Crime is down and so not oft reported in articles like this. VC funded articles and social movements are loudly screaming about it. VC / billionaire fanboys are happy to pick up the slack in the comment section.

It's both. Some media spends every minute talking about it and some will completely ignore the topic even when its central to the topic being discussed. Also with social media, most people are seeing this themselves and bypassing commercial news.

Media isn't monolithic. Local media tends to ignore or downplay crime--I think in part because the writers are either insulated from it or have their own political biases. National media plays up the crime because they like to use SF as a whipping horse to say "see don't be like SF or your city will have full blown anarchy". SF is actually a huge anchor on national progressives because republicans can always point to SF and show how poorly policies have played out. If SF was as clean/safe as Copenhagen, it'd be a lot harder to make that argument. SF progressives are a different breed altogether though--it's all about scolding people and identity politics to distract from meaningful policies like universal healthcare, elder/child-care, etc.