Ask HN: Why is Facebook on the rack for questionable practices but not LinkedIn?

Partly because of Cambridge Analytica and The Guardian's interest in that organisation (an interest somewhat motivated by CA's role in promoting brexit).

Basically politics.

n.b. don't misread this as me claiming that FB and CA are being unjustifiably maligned.

Such as?

edit: I'm not implying LinkedIn doesn't have any bad practices or issues. But it helps to know which ones you have in mind so we know exactly which apples and oranges are being compared.