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Except that is the AGPL not the GPL which allows you to run free software as a service.

Also, a commercialization clause (that is probably incompatible with the GPL) is not the same as a dual licence.

Correct, a commercialization clause is clearly incompatible with the GPL as is mentioned in their FAQ: http://www.gnu.org/licenses/gpl-faq.html#NoMilitary

So short of proper dual-licensing (which this isn't), that clause isn't valid.