It is no longer open source, there’s no doubt about it. You may have a free beer license to it as long as elastic grants you one, but you have no right to modify, patch, redistribute as you see fit.
Open source projects that relied on ES are cut off.
You are still free to modify the code, patch or redistribute it under the terms of the SSPL. If you prefer the ESL, you may only modify the code, but not redistribute it.
Now, if you were distributing a GPL product that included ES, you will have significant problems, since the GPL and SSPL are not compatible - so you may in fact be unable to distribute the whole product anymore, which probably caused huge disruptions to some projects - so I'm not in any way saying that what they did is nice. But it was definitely not making it closed source, not in spirit and not in effect.
Open source projects that relied on ES are cut off.