Even though I don't use twitter feeds or trackers, I don't think banning them now would be good for the game...
Niantic should just find a way to block it (randomize spawns maybe like how they did shiny magikarp) and leave it at that.
I'm sure some people who use trackers honestly don't think they are cheating and they were introduced to the game this way and everyone in their group does it. It's a bit harsh to ban them all for something that Niantic does practically NOTHING about and hasn't even warned in game clearly that using a tracker is bad/cheating.
I stopped using it myself and even twitter feeds because it wasn't as exciting if you know so and so is going to be here at this exact spot and it's IVs/moves, etc...I was also too lazy to really drive far away to catch 100% stuff or rare mons so I also don't bother (don't want to waste gas neither)...Completing the dex was also low on my game goals so I care little that I still don't have a Porygon/Aerodactyl/usable Snorlax, Dragonite, etc...
I remember first seeing a tracker and a fellow lady trainer telling us about it and we all thought, WOW, if we had this, we would've found that Lapras we saw in sightings (shadow) just last week instead of wandering aimlessly for 15-20 minutes! (and my wife STILL doesn't have a Lapras since playing since July)...
All that said, randomize spawns and trackers all break (yay!).
I still thinks it's stupid that there are spawn points so when I walk around in my neighborhood, I know NOTHING will ever spawn on this part of my path, etc...It loses it's magic/surprise when you sorta know too much.