I suppose my personal experience varies from that a bit. I agree Comcast has a horribly shady past abusing their customers.
Cloudflare's origins are lesser known, likely even to those currently working for them. That doesn't really matter for this purpose I suppose. Former volunteer for their previous honeypot project
In the end, I have no contracts with anyone stating how my data may be (ab)used or how long it will exist. So instead of one company potentially abusing my data, now it is two. There is really no way around that other than to not participate. My personal preference is to assume the Only Two Rules. [1]
In full disclosure, I use neither of those services for DNS but my I would not expect non-HN people to use my convoluted process combining open source VPN meshes, dozens of unbound caches and dozens on many VPS providers that talk to upstream DoT resolvers with cron jobs that pre-cache thousands of domains in random orders using "shuf" that I do not visit and dozens that I do visit and unbound configured to both override min-ttl and to hold onto 0-ttl records until requested again and running the same cron jobs on my home firewalls that talk to those VPS nodes over DoT and Tinc.
[1] - https://www.youtube.com/watch?v=Wxi-IUnCN_8 [video]