It is (mis)using inductive reasoning: going from the specific to the general.
X, Y, and Z people have used yoga and have also been Satanists, or allegedly ended up with demonic possession/oppression, therefore, yoga must be bad.
Which really isn’t true at all, and not even necessarily related. People can misuse all sorts of things without the object being intrinsically evil. Intrinsic evil has a very specific usage in Catholic moral theology. It means something is evil in of itself.
I think it’s a common mistake for people to underestimate how big the world is, with its 7 billion inhabitants. I think many people don’t appreciate that if you look hard enough, you’re going to almost always find an example of something being used badly.
The reality is that Hinduism, like other faith traditions of the East, came about and developed over a very long time span. It has had people who have loved, hated, married, warred, invented, dreamed, died, searched for God as they knew how, and did everything else that human beings do. They are not angels and they are not demons. But they were made in the image of God and they have a lot to offer to the world, and even if some or even a lot of their spiritual beliefs are not compatible with Magisterial teachings, that doesn’t mean they shouldn’t be treated with respect, and that doesn’t mean the many arts they practiced and explored don’t have value.
India is going to be the world’s greatest superpower in another 2-3 generations - bigger than China or the US - and maybe they’ll be easier to evangelize if we don’t treat everything about their culture like it was radioactive.