"Free trials should not require a credit card."
This is opinion presented as fact. This is not a dark pattern. Totally unrestricted free trials are wonderful, you've invested a ton in your product and you want a prospective customer to experience everything. But there are legions of abusers and bad actors of all kinds. Having an opt-in to use/abuse your platform for 2 weeks is not always viable. Card up front is not a perfect filter, but it's helpful in turning this noise way down and letting you focus on helping actual prospective customers become successful with your product.