@georgeob1,
Might well be that I'm partisan, but I really didn't write those reports.
Citizens of the EU and their family members have the right to move, reside, and work freely within the territory of the EU, subject to certain conditions.
I do think that the status of UK-citizens in EU-countries and EU-citizens in the UK in the past-Brexit period is one of the key ponts during the negotiations - at least, if I trust what is said and has been published.
Americans (and other non-EU-nationals) living in Spain are doing so under different EU regulations than Article 21 of the Treaty on the Functioning of the European Union.