I just cancelled and it was relatively painless, to their credit.
When they asked the reason, I said that political coverage was unfair. Left is OK, unfair is not.
I don't consider myself "on the left" but I really don't mind a publication being left of center or right of center. If it's good, I will pay for it (I subscribed tp The Atlantic at least twice, and the New Yorker once, and probably others in a mix of print and digital).
But the NYT has drifted too far down the path of politically-correct fashions, and away from robust debate and discussion of challenging topics and how they intersect with real events.
It feels more like they want to persuade me to hold a set of opinions (which shifts rapidly), rather than informing me and letting me form my own. "Persuade" is even the wrong word; more like "pressure" or "coerce". If it's all ads, so be it; but when I pay, I expect that I am the customer and not the product. So I don't pay as of the end of my billing cycle.
Also, the NYT cheers on, and even participates in bullying. Scott Alexander being a recent example, but there are a lot more when it comes to politically-charged topics.
I should reiterate that this is not a right-left thing. I would have remained subscribed if the NYT had simply drifted left, and concerned itself mainly with arguments betweed various left-of-center factions. Lots of worthwhile things to discuss and debate there, and lots of events to tie it to.