I don't think that's dark UX, it's just shitty UI design. What bugs me the most about LastPass is how it tries to be so damned helpful and offers to fill in credentials on sites that they clearly don't belong to, or offers to save credentials on a site where I alredy clicked "don't save" 1000 times, no really, I don't want to save my private passwords in my company vault thank you very much, why the f$%& don't you have a "don't bug me again" checkbox in this sh*$$y popup?!