If I pay for grammarly, and it plagiarizes an existing work but represents it as an entirely new, independent work and I am unaware of the existing work that is being stolen, who is doing the stealing?
This makes more sense for text message auto complete: you just take the suggested next word after a one word start deed, it might reproduce a Wikipedia entry. But what did tub expect? The same would be true with grammarly if you somehow got it to produce a bunch of new text. You expected garbage, but somehow infringed on copyright instead. But I guess think the user deserves some responsibility in realizing their expected garbage output isn’t for some reason.
If you pay a shady character to get you a modern laptop for $100 you can't claim that you were unaware that it was most likely stolen and the fact that you paid for it something doesn't absolve you morally.