Their aggressive, misleading and clickbait ads, particularly as YouTube sponsorships. From my experience the product is fine, but the ads make it seem like their covering up for something.
Adding to this, there’s probably a general feeling that, especially with publicly traded companies (which Nord isn’t… yet), profit motive will inevitably cause a company to make decisions that don’t align with its customer’s best interests. The idealist in me thinks it’s possible for a company to be profitable without being shitty towards its customers. The cynic in me thinks there’s probably more profit in being shitty.
That said, profit keeps companies in business. If you’re getting it for free, you’re either the product, pirating it, or relying on others to keep it going. I won’t say paying for it guarantees future availability and development, but that profit motive also motivates continuing development. Kind of a double edged sword, there.