Shouldn't it be "the best anti-user company"? Otherwise it sounds like the company being worst at enforcing anti-user policy, i.e. failing to do it right, i.e. being user-friendly after all.
Even better would be: "the most user-unfriendly company".
Even better would be: "the most user-unfriendly company".
But joking aside, I was wondering whether to say 'best' or 'worst'; I didn't even think of saying 'most'.