Remember who writes the NEC - it's the NFPA. They have a standard which applies to chimneys (though it's not a chimney standard). But if local AHJ's don't adopt the publication, then lightning systems are not required. Some AHJ's require it and some don't; many require it on some buildings but not all.
So it would be unfair to say the NFPA addresses antennae and not chinmeys.
As iwire said, the antenna is electrical while the chimney is not.
It's NFPA 780 for lightning and it does indeed address chimneys. In a nutshell, a chimney not within the zone of protection of a strike termination device (air terminal or lightning rod) needs its own, or needs to be bonded to the system. If within a zone of protection, nothing needs to be done. Note the bonding requirements. If grounding attracted lightning, it sure wouldn't be required by the NFPA. The intentional path to ground is there to DIRECT lighting energy, is does not ATTRACT it one bit.
4.8.8 Chimneys and Vents. Strike termination devices shall be required on all chimneys and vents that are not located within a zone of protection, including metal chimneys having a metal thickness of less than 4.8 mm (3/16 in.).
4.8.8.1 Chimneys or vents with a metal thickness of 4.8 mm (3/16 in.) or more shall require only a connection to the lightning protection system.
4.8.8.2 The connection for 4.8.8.1 shall be made using a main-size lightning conductor and a bonding device that has a surface contact area of not less than 1940 mm 2 (3 in.2) and shall provide two or more paths to ground, as is required for strike termination devices.4.8.8.3 Required strike termination devices shall be installed on chimneys and vents, as shown in Figure 4.8.8.3, so that the distance from a strike termination device to an outside corner or the distance perpendicular to an outside edge shall be not greater than 0.6 m (2 ft).
Here is the rest of NFPA 780:
http://www.uscg.mil/petaluma/TPF/ET_SMS/Manuals/NFPA_780.pdf