2 reasons imo.
1. There is a perception that spinners are more likely to chuck, so fast bowlers are somewhat overlooked.
2. Junaid is no world beater so he has little attention on him. Ajmal was making bunnies out of world class batsmen so even players were complaining through twitter, etc...
Or shoaib akhter for example was causing people problems so there was more attention on him regarding his action.
Junaid poses no risk to any world class batsmen and barely gets picked for internationals anymore, so no one cares.