Dry Rub Spare Ribs

I thought this recipe was average at best and Lisa and Ben did not like them at all.  I guess this will not be made at our house again.
 

Ingredients
2-3 racks of spare ribs
3 tablespoons kosher salt  
3 tablespoons whole black peppercorns  
2 tablespoons sugar  
1 1/2 tablespoons whole mustard seeds  
1 1/2 tablespoons sweet paprika  
2 teaspoons dried oregano  
1 1/2 teaspoons whole cumin seeds  
1 1/2 teaspoons fennel seeds  
1 1/2 teaspoons celery seeds  
1 1/2 teaspoons crushed red pepper flakes  
1 teaspoon dried thyme

Make the rub: in a spice grinder or blender, pulse the rub ingredients for a few seconds until the seeds are coarsely ground; do in two batches, if necessary; the rub should have a slightly coarse texture.

Preheat the Big Green to 300 indirect.

Spread the rub generously on all sides of the ribs and let stand at room temperature for 20-30 minutes before grilling.

Grill the ribs, rib side down, over indirect medium heat until the meat is very tender and has pulled back from the ends of the bones, 2½ to 3 hours.

 

Remove from the grill and allow to rest for 5-10 minutes before slicing into individual ribs.