The response to GDPR is interesting. If they are handling and selling your data in ways that are not compatible with GDPR, then you should seriously consider using someone else for that information.
> If they are handling and selling your data in ways that are not compatible with GDPR
Very few businesses actually sell data the way you are imagining and if all GDPR did was ban that business model I would be happy with the existence of GDPR. GDPR is much more than that and this insinuation that every business that doesn't want to deal with this hassle is somehow evil and selling ultra detailed profiles on you to the highest bidder is highly mistaken.
Until that gets sorted out lots of sites are going to start doing this out of desperation.