The coalition for Afghanistan was voluntary. This isn't even that, it's just flying our planes over Spain's airspace.
Even as a joint contributor I see no reason for the US to pay for bases it's never going to be allowed to use.
> After the 9/11 attacks on the United States, the North Atlantic Treaty Organization Allies invoked Article 5 of the Washington Treaty, the collective-defense clause, for the first time in NATO's history.
No LLM needed, nor used. Direct from the US State Department!
> Even as a joint contributor I see no reason for the US to pay for bases it's never going to be allowed to use.
It continues to be able to use them. It has never been allowed to use them for things Spain finds objectionable.
I'm not clear on how a semantic quibble that amounts to "Spain and the rest of Europe proactively affirmed their Article 5 obligations to the US" helps your case here. You have, if anything, effectively demonstrated Spain's commitment to the agreement.
> The United States has never activated article 5
The US didn't activate it. It was:
> The decision to invoke NATO's collective self-defense provisions was undertaken at NATO's own initiative, without a request by the United States
source: https://en.wikipedia.org/wiki/2001_NATO_Article_5_contingenc...
Regardless, article 5 was activated _on behalf_ of the US, if not at the US's request.
Which isn't the situation being imposed by Spain. They're being told they can't use the airspace for one specific military action. They maintain use of their bases in other ways (training, presumably ship refueling, maintenance, etc). They may be able to use the airspace for _other_ military actions in the future.