Taweez is a gift from Allah SWT and if someone can get a proper Amil to give him one, he should be grateful to Allah SWT. Taweez are used for different purposes. They are used for rubbing on the body, boiling in water for drinking and for wearing for protection from Black Magic.
It is understood that Allah SWT is the one who does. There is no argument against this, but in Islam we are told to use asbab. What would you say about someone who refuses to wear warm clothes in the winter calling it shirk because it is Allah SWT who protects from the cold. After he becomes sick, he will probably cry in Tahajjud, begging Allah SWT to cure him, with warm clothes right next to him.
Let’s compare Taweez to medicine. Some medicines are taken in the form of tablets and syrup. Others, however, have to be applied on the body, for wounds, cuts etc. Not all medicine has to be taken through the mouth. Similarly, while a person may read the Holy Quran, it does not mean that he cannot wear Taweez.
When Amils write Taweez, sometimes we may not be able to undertand what is written with Musk, Zafraan or even a simple pen. This is supposed to humble us and consider Amils very knowledgeable in their field. If we don’t know something, it is lack of knowlegde on our part, not shirk.
There are a lot of websites and people bent on misleading people with their so called knowledge that lacks depth and insight. They spare no efforts in advancing their shirk propaganda and taking people away from cures. These people should do taubah and astaghfar for calling Taweez shirk. According to scholars, calling Taweez shirk is shirk in itself. In this day and age we should use our common sense and stay well away from such websites and people.