Actually it's the re-opening that's not working.
+10,000

The errors in reasoning going on are basic, but:

1) Compliance. You can mandate masks all you want and it's great if this improves mask wearing in public places, that is reason enough to favor a mandate period. But if people have house parties without masks noone is enforcing it, if employers are letting people not wear masks especially in indoor jobs that's illegal and a problem (probably more low wage jobs where this happens), if people are living in extremely crowded conditions and not wearing masks at home it can be a problem too.
2) Even with perfect compliance, people wear masks at house parties, masks are not 100% effective. That masks are not 100% effective is being used to argue that masks are 0% effective is a real reasoning error. Black and white, all or nothing thinking.

In order to prove that masks aren't helping you would need some alternate California where noone was wearing masks and there were no laws to wear masks and show "no difference in cases". This doesn't exist. The states that are doing well in comparison to California pretty much all require masks and have weeks before California did. But it wasn't the only policy. I think there is some straw manning going on that many people advocate masks as the ONLY policy. Hint: if politicians do this follow the money, and if Trump admin does it just ignore it, but public health advocates mostly don't, politicians being rather corruptible, well that's not news.

San Francisco never re-opened indoor dining and our daily case count remains stable, with 52, 42 and 31 for the last 3 days. Orange County, on the other hand, reopened them mid-June and had 646 cases today. They have 4x the population but 10x the new daily cases.
L.A. county is reporting near 5k cases today (that includes backlog so average is more like 2-3k). Restaurants were opened end of May. They are planning on 15% of people to have got it by December. The number of people who got it in NYC in the peak was only 20% or so based on what we hear about antibodies. Yes if it's spread out in time it won't overwhelm hospitals. But they WANT to infect 15%, that is literally THE PLAN.