Two things can be at the same time.
The world is ancient and occultists are known to thrive on seeking higher knowledge through old practices and learning.
If you try and find theistic satanist groups all you can find is historic groups and so it feeds both the side of theistic satanism being a bogeyman, but also theistic satanism being actively trying to conceal itself due to the nature of people and acts that would tie back to that kind of belief system.
By their nature (what I know of theistic satanism) they would absolutely thrive on muddying the waters and mixing historic antisemitic practices with debasing religion generally - heck - athiest satanism is as easily applicable to that causing of outrage and iconoclastic belief. However, theistic satanism teaches that the teachings of God should be inverted and perverted in every way.
Alaistair Crowley claimed to have broken every commandment and committed every sin he could - there is lots of speculation how credible he was - but he was prolific so I think he makes a good example.
In saying that, if there was a cabal of occult-led rather than theistic satanic (more likely) then seeking the truth and meaning behind the original blood libel (i.e looking beyond slander to origin source ritual or grain of truth) makes sense as that is par for the course in that world to dissect everything searching for the hidden wisdom.
On a surface level, there are likely grunting white nationalists that latched onto means of slurring jews in a sly way, but its more likely that the toilet bowl of social media has run with an idea and that there is some truth to the occultism (see Freemasonry, Illuminati, other secret societies that exist) that has been separately leaked and some guru has stirred it all together.
I do remember a video on youtube by a member of the band The Scorpions who said he was invited to a dinner party/event that resembled occultism/theistic satanism and involved human sacrifice -- so there is material out there that people can draw from to make these conclusions literally, too.